diff --git a/src/2024062806.md b/out/parse.md
similarity index 100%
rename from src/2024062806.md
rename to out/parse.md
diff --git a/src/2024062806.pdf b/out/parse.pdf
similarity index 100%
rename from src/2024062806.pdf
rename to out/parse.pdf
diff --git a/src/Makefile b/src/Makefile
index 86a7bc0..5618022 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1,34 +1,31 @@
 # Makefile for C-Minus
 #
 # ./lex/tiny.l        --> ./cminus.l (from Project 1)
-# ./yacc/tiny.y       --> ./cminus.y
-# ./yacc/globals.h    --> ./globals.h
+# ./yacc/tiny.y       --> ./cminus.y (from Project 2)
+# ./yacc/globals.h    --> ./globals.h (from Project 2)
 
 CC = gcc
 
-CFLAGS = -W -Wall
+CFLAGS = -W -Wall -g
 
-OBJS = main.o util.o lex.yy.o y.tab.o
+OBJS = main.o util.o lex.yy.o y.tab.o symtab.o analyze.o
 
 .PHONY: all clean
-all: cminus_parser
+all: cminus_semantic
 
 clean:
-	rm -vf cminus_parser *.o lex.yy.c y.tab.c y.tab.h y.output
+	rm -vf cminus_semantic *.o lex.yy.c y.tab.c y.tab.h y.output
 
-cminus_parser: $(OBJS)
+cminus_semantic: $(OBJS)
 	$(CC) $(CFLAGS) $(OBJS) -o $@ -lfl
 
-main.o: main.c globals.h util.h scan.h parse.h y.tab.h
+main.o: main.c globals.h util.h scan.h parse.h y.tab.h analyze.h
 	$(CC) $(CFLAGS) -c main.c
 
 util.o: util.c util.h globals.h y.tab.h
 	$(CC) $(CFLAGS) -c util.c
 
-scan.o: scan.c scan.h util.h globals.h y.tab.h
-	$(CC) $(CFLAGS) -c scan.c
-
-lex.yy.o: lex.yy.c scan.h util.h globals.h y.tab.h
+lex.yy.o: lex.yy.c scan.h globals.h y.tab.h util.h
 	$(CC) $(CFLAGS) -c lex.yy.c
 
 lex.yy.c: cminus.l
@@ -40,4 +37,10 @@ y.tab.o: y.tab.c parse.h
 	$(CC) $(CFLAGS) -c y.tab.c
 
 y.tab.c: cminus.y
-	yacc -d -Wcounterexamples -v cminus.y
+	yacc -d -v cminus.y
+
+analyze.o: analyze.c analyze.h globals.h y.tab.h symtab.h util.h
+	$(CC) $(CFLAGS) -c analyze.c
+
+symtab.o: symtab.c symtab.h
+	$(CC) $(CFLAGS) -c symtab.c
diff --git a/src/analyze.c b/src/analyze.c
index 61d2400..b092cc1 100644
--- a/src/analyze.c
+++ b/src/analyze.c
@@ -1,159 +1,315 @@
 /****************************************************/
 /* File: analyze.c                                  */
 /* Semantic analyzer implementation                 */
-/* for the TINY compiler                            */
-/* Compiler Construction: Principles and Practice   */
-/* Kenneth C. Louden                                */
+/* for the CMinus compiler                          */
+/* Yenru0                                           */
 /****************************************************/
 
+#include "analyze.h"
 #include "globals.h"
 #include "symtab.h"
-#include "analyze.h"
 
-/* counter for variable memory locations */
-static int location = 0;
+static void symbolError(TreeNode *t, char *message) {
+    fprintf(listing, "Symbol error at line %d: %s\n", t->lineno, message);
+    Error = TRUE;
+    exit(-1);
+}
+
+static BucketList func_entry = NULL;
+static Scope func_scope;
+static TreeNode *func_params[256];
+static int func_param_count = 0;
 
 /* Procedure traverse is a generic recursive 
  * syntax tree traversal routine:
  * it applies preProc in preorder and postProc 
  * in postorder to tree pointed to by t
  */
-static void traverse( TreeNode * t,
-               void (* preProc) (TreeNode *),
-               void (* postProc) (TreeNode *) )
-{ if (t != NULL)
-  { preProc(t);
-    { int i;
-      for (i=0; i < MAXCHILDREN; i++)
-        traverse(t->child[i],preProc,postProc);
+static void traverse(TreeNode *t,
+                     void (*preProc)(TreeNode *),
+                     void (*postProc)(TreeNode *)) {
+    if (t != NULL) {
+        preProc(t);
+        {
+            int i;
+            for (i = 0; i < MAXCHILDREN; i++)
+                traverse(t->child[i], preProc, postProc);
+        }
+        postProc(t);
+        traverse(t->sibling, preProc, postProc);
     }
-    postProc(t);
-    traverse(t->sibling,preProc,postProc);
-  }
 }
 
 /* nullProc is a do-nothing procedure to 
  * generate preorder-only or postorder-only
  * traversals from traverse
  */
-static void nullProc(TreeNode * t)
-{ if (t==NULL) return;
-  else return;
+static void nullProc(TreeNode *t) {
+    if (t == NULL) return;
+    else
+        return;
 }
 
 /* Procedure insertNode inserts 
  * identifiers stored in t into 
  * the symbol table 
  */
-static void insertNode( TreeNode * t)
-{ switch (t->nodekind)
-  { case StmtK:
-      switch (t->kind.stmt)
-      { case AssignK:
-        case ReadK:
-          if (st_lookup(t->attr.name) == -1)
-          /* not yet in table, so treat as new definition */
-            st_insert(t->attr.name,t->lineno,location++);
-          else
-          /* already in table, so ignore location, 
-             add line number of use only */ 
-            st_insert(t->attr.name,t->lineno,0);
-          break;
+static void insertNode(TreeNode *t) {
+    //printf("Insert Node: line %d\n", t->lineno);
+    switch (t->nodekind) {
+        case ExpK:
+            switch (t->kind.exp) {
+                case IdK:
+                case ArrIdK:
+                case CallK: {
+                    BucketList entry = st_lookup(t->attr.name);
+                    if (entry == NULL) {
+                        symbolError(t, "Undeclared Symbol");
+                    } else {
+                        // t->type = entry->type;// TODO: Ambiguity
+                        t->scope = curr_scope();
+                        st_entry_insert_line(entry, t->lineno);
+                        t->type = entry->type;
+                    }
+                }
+                default:
+                    break;
+            }
+            break;
+        case StmtK:
+            switch (t->kind.stmt) {
+                case CompK:
+                    if (func_scope != NULL) {
+                        push_scope(func_scope);
+                        func_scope = NULL;
+                        for (int i = 0; i < func_param_count; i++) {
+                            TreeNode *param = func_params[i];
+                            func_entry->param_types[func_entry->param_count++] = param->type;
+                            if (st_lookup_current(param->attr.name) != NULL) {
+                                symbolError(param, "Redefinition of a Parameter");
+                            } else {
+                                st_try_insert(param->attr.name, SymbolParam, param->type, param->lineno);
+                            }
+                        }
+                        func_entry = NULL;
+                        func_scope = NULL;
+                        func_param_count = 0;
+                    } else {
+                        push_scope(scope_new("compound"));
+                    }
+                    break;
+                default:
+                    break;
+            }
+            break;
+
+        case DeclK:
+            switch (t->kind.decl) {
+                case FuncK:
+                    if (st_lookup(t->attr.name) != NULL) {
+                        symbolError(t, "Redefinition of a Function");
+                    } else {
+                        func_entry = st_try_insert(t->attr.name, SymbolFunc, t->type, t->lineno);
+                        t->scope = curr_scope();
+                    }
+
+                    func_scope = scope_new(t->attr.name);
+                    //push_scope(scope_new(t->attr.name));
+                    break;
+                case ArrParamK:
+                case NonArrParamK: {
+
+                    if (t->type != Void) {
+                        func_params[func_param_count++] = t;
+                    }
+
+                }
+
+                break;
+                case VarK:
+                case ArrVarK:
+                    if (st_lookup_current(t->attr.name) != NULL) {
+                        symbolError(t, "Redefinition of a Variable");
+                    } else {
+                        if (t->type == Void) {
+                            symbolError(t, "Variable cannot be of type void");
+                            break;
+                        }
+                        t->scope = curr_scope();
+                        st_try_insert(t->attr.name, SymbolVar, t->type, t->lineno);
+                    }
+                    break;
+                default:
+                    break;
+            }
+            break;
         default:
-          break;
-      }
-      break;
-    case ExpK:
-      switch (t->kind.exp)
-      { case IdK:
-          if (st_lookup(t->attr.name) == -1)
-          /* not yet in table, so treat as new definition */
-            st_insert(t->attr.name,t->lineno,location++);
-          else
-          /* already in table, so ignore location, 
-             add line number of use only */ 
-            st_insert(t->attr.name,t->lineno,0);
-          break;
-        default:
-          break;
-      }
-      break;
-    default:
-      break;
-  }
+            break;
+    }
+}
+
+static void afterNode(TreeNode *t) {
+    if (t->nodekind == StmtK && t->kind.stmt == CompK) {
+        pop_scope();
+    }
 }
 
 /* Function buildSymtab constructs the symbol 
  * table by preorder traversal of the syntax tree
  */
-void buildSymtab(TreeNode * syntaxTree)
-{ traverse(syntaxTree,insertNode,nullProc);
-  if (TraceAnalyze)
-  { fprintf(listing,"\nSymbol table:\n\n");
-    printSymTab(listing);
-  }
+void buildSymtab(TreeNode *syntaxTree) {
+    st_init();
+    BucketList entry;
+    entry = st_try_insert("input", SymbolFunc, Integer, 0);
+    entry->param_count = 0;
+
+    entry = st_try_insert("output", SymbolFunc, Void, 0);
+    entry->param_types[0] = Integer;
+    entry->param_count = 1;
+
+    traverse(syntaxTree, insertNode, afterNode);
+    if (TraceAnalyze) {
+        fprintf(listing, "\nSymbol table:\n\n");
+        printSymTab(listing);
+    }
 }
 
-static void typeError(TreeNode * t, char * message)
-{ fprintf(listing,"Type error at line %d: %s\n",t->lineno,message);
-  Error = TRUE;
+static void typeError(TreeNode *t, char *message) {
+    fprintf(listing, "Type error at line %d: %s\n", t->lineno, message);
+    Error = TRUE;
 }
 
-/* Procedure checkNode performs
- * type checking at a single tree node
- */
-static void checkNode(TreeNode * t)
-{ switch (t->nodekind)
-  { case ExpK:
-      switch (t->kind.exp)
-      { case OpK:
-          if ((t->child[0]->type != Integer) ||
-              (t->child[1]->type != Integer))
-            typeError(t,"Op applied to non-integer");
-          if ((t->attr.op == EQ) || (t->attr.op == LT))
-            t->type = Boolean;
-          else
-            t->type = Integer;
-          break;
-        case ConstK:
-        case IdK:
-          t->type = Integer;
-          break;
-        default:
-          break;
-      }
-      break;
-    case StmtK:
-      switch (t->kind.stmt)
-      { case IfK:
-          if (t->child[0]->type == Integer)
-            typeError(t->child[0],"if test is not Boolean");
-          break;
-        case AssignK:
-          if (t->child[0]->type != Integer)
-            typeError(t->child[0],"assignment of non-integer value");
-          break;
-        case WriteK:
-          if (t->child[0]->type != Integer)
-            typeError(t->child[0],"write of non-integer value");
-          break;
-        case RepeatK:
-          if (t->child[1]->type == Integer)
-            typeError(t->child[1],"repeat test is not Boolean");
-          break;
-        default:
-          break;
-      }
-      break;
-    default:
-      break;
+static void beforeCheckNode(TreeNode *t) {
+    if (t->nodekind == DeclK && t->kind.decl == FuncK) {
+        func_entry = st_lookup(t->attr.name);
+    }
+}
+static void checkNode(TreeNode *t) {
+    switch (t->nodekind) {
+        case ExpK:
+            switch (t->kind.exp) {
+                case OpK: {
+                    TreeNode *left = t->child[0];
+                    TreeNode *right = t->child[1];
+                    if (left->type != Integer || right->type != Integer) {
+                        typeError(t, "Operator applied to non-integer");
+                    }
+                    t->type = Integer;
 
-  }
+                } break;
+                case ConstK:
+                    t->type = Integer;
+                    break;
+                case IdK: {
+                    BucketList entry = st_lookup_from(t->attr.name, t->scope);
+                    t->type = entry->type;
+
+                } break;
+                case ArrIdK: {
+                    if (t->child[0]->type != Integer) {
+                        typeError(t, "Array subscript is not an integer");
+                    }
+                    t->type = IntegerArray;
+
+                } break;
+
+                case AssignK: {
+                    TreeNode *left = t->child[0];
+                    TreeNode *right = t->child[1];
+                    if (left->type != right->type) {
+                        typeError(t, "Assignment of different types");
+                    }
+                    t->type = left->type;
+
+                } break;
+                case CallK: {
+                    BucketList entry = st_lookup_from(t->attr.name, t->scope);// not null
+
+                    if (entry->symbolKind != SymbolFunc) {
+                        typeError(t, "Call to a non-function");
+                    }
+
+                    TreeNode *arg = t->child[0];
+
+                    int i = 0;// 파라미터 인덱스
+
+                    while (arg != NULL && i < entry->param_count) {
+                        if (arg->type != entry->param_types[i]) {
+                            typeError(t, "Type mismatch in argument: Expected different type");
+                        }
+
+                        arg = arg->sibling;
+                        i++;
+                    }
+
+                    if (arg != NULL) {
+                        typeError(t, "Too many arguments in function call");
+                    } else if (i < entry->param_count) {
+                        typeError(t, "Too few arguments in function call");
+                    }
+
+                    t->type = entry->returnType;
+
+                } break;
+                default:
+                    break;
+            }
+            break;
+        case StmtK:
+            switch (t->kind.stmt) {
+                case ReturnK: {
+
+                    if (func_entry == NULL) {
+                        typeError(t, "Return statement is not in a function");
+                        break;
+                    }
+                    TreeNode *retval = t->child[0]; /* nullalbe */
+                    if (func_entry->returnType == Void) {
+                        if (retval != NULL) {
+                            typeError(t, "Return with a value in a void function");
+                        }
+                    } else {
+                        if (retval == NULL) {
+                            typeError(t, "Return without a value in a non-void function");
+                        } else if (retval->type != func_entry->returnType) {
+                            typeError(t, "Return type mismatch");
+                        }
+                    }
+                } break;
+                case IterK: {
+                    TreeNode *condition = t->child[0];
+                    if (condition->type != Integer) {
+                        typeError(t, "While condition is not of type integer");
+                    }
+                } break;
+                case IfK: {
+                    TreeNode *condition = t->child[0];
+                    if (condition->type != Integer) {
+                        typeError(t, "If condition is not of type integer");
+                    }
+                } break;
+                default:
+                    break;
+            }
+            break;
+
+        case DeclK:
+            switch (t->kind.decl) {
+            
+                case FuncK:
+                    func_entry = NULL;
+                    break;
+                default:
+                    break;
+            }
+        default:
+            break;
+    }
 }
 
 /* Procedure typeCheck performs type checking 
  * by a postorder syntax tree traversal
  */
-void typeCheck(TreeNode * syntaxTree)
-{ traverse(syntaxTree,nullProc,checkNode);
+void typeCheck(TreeNode *syntaxTree) {
+    traverse(syntaxTree, beforeCheckNode, checkNode);
 }
diff --git a/src/globals.h b/src/globals.h
index 37446ee..c9df1b7 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -14,6 +14,9 @@
 #include <stdlib.h>
 #include <string.h>
 
+struct Scope;
+typedef struct Scope *Scope;
+
 #ifndef FALSE
 #define FALSE 0
 #endif
@@ -103,7 +106,14 @@ typedef enum { TypeNameK } TypeKind;
 /* ExpType is used for type checking */
 typedef enum { Void,
                Integer,
-               IntegerArray } ExpType;
+               IntegerArray
+} ExpType;
+
+typedef enum {
+    SymbolVar,
+    SymbolFunc,
+    SymbolParam
+} SymbolKind;
 
 #define MAXCHILDREN 3
 
@@ -124,6 +134,7 @@ typedef struct treeNode {
         char *name;
     } attr;
     ExpType type; /* for type checking of exps */
+    Scope scope;
 } TreeNode;
 
 /**************************************************/
diff --git a/src/main.c b/src/main.c
index a94af77..98a062a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -10,7 +10,7 @@
 /* set NO_PARSE to TRUE to get a scanner-only compiler */
 #define NO_PARSE FALSE
 /* set NO_ANALYZE to TRUE to get a parser-only compiler */
-#define NO_ANALYZE TRUE
+#define NO_ANALYZE FALSE
 
 /* set NO_CODE to TRUE to get a compiler that does not
  * generate code
@@ -40,7 +40,7 @@ FILE *code;
 int EchoSource = FALSE;
 int TraceScan = FALSE;
 int TraceParse = TRUE;
-int TraceAnalyze = FALSE;
+int TraceAnalyze = TRUE;
 int TraceCode = FALSE;
 
 int Error = FALSE;
diff --git a/src/symtab.c b/src/symtab.c
index 86b9f49..aa472a7 100644
--- a/src/symtab.c
+++ b/src/symtab.c
@@ -4,8 +4,6 @@
 /* (allows only one symbol table)                   */
 /* Symbol table is implemented as a chained         */
 /* hash table                                       */
-/* Compiler Construction: Principles and Practice   */
-/* Kenneth C. Louden                                */
 /****************************************************/
 
 #include "symtab.h"
@@ -13,6 +11,17 @@
 #include <stdlib.h>
 #include <string.h>
 
+Scope scope_stack[MAX_SCOPE_DEPTH];
+int scope_stack_top = -1;
+Scope scope_global;// no sibling no parent
+
+void st_init(void) {
+    scope_global = scope_new("global");
+    scope_global->depth = 0;
+    scope_stack_top = 0;
+    scope_stack[scope_stack_top] = scope_global;
+}
+
 /* SHIFT is the power of two used as multiplier
    in hash function  */
 #define SHIFT 4
@@ -28,79 +37,213 @@ static int hash(char *key) {
     return temp;
 }
 
-Scope curr_scope(void) {
-    if (top_stack == -1) {
-        return NULL;
+Scope scope_new(char *scope_name) {// it
+    Scope new_scope = (Scope) malloc(sizeof(struct Scope));
+    new_scope->name = scope_name;
+    new_scope->depth = -1;
+    new_scope->parent = NULL;
+    new_scope->child = NULL;
+    new_scope->child_last = NULL;
+    new_scope->next_sibling = NULL;
+
+    new_scope->location = 0;
+    return new_scope;
+}
+
+void pop_scope(void) {
+    if (scope_stack_top == -1) {// empty
+        return;
     } else {
-        return scope_stack[top_stack];
+        scope_stack[scope_stack_top] = NULL;
+        scope_stack_top--;
     }
 }
 
-/* Procedure st_insert inserts line numbers and
- * memory locations into the symbol table
- * loc = memory location is inserted only the
- * first time, otherwise ignored
- */
-void st_insert(char *name, int lineno, int loc) {
+void push_scope(Scope scope) {
+    if (scope_stack_top == MAX_SCOPE_DEPTH - 1) {// full
+        return;
+    } else {
+        Scope before = curr_scope();
+        if (before->child == NULL) {
+            before->child = scope;
+            before->child_last = scope;
+        } else {
+            before->child_last->next_sibling = scope;
+            before->child_last = scope;
+        }
+        scope->parent = before;
+        scope->depth = before->depth + 1;
+
+        scope_stack_top++;
+        scope_stack[scope_stack_top] = scope;
+    }
+}
+
+Scope curr_scope(void) {
+    if (scope_stack_top == -1) {
+        return NULL;
+    } else {
+        return scope_stack[scope_stack_top];
+    }
+}
+
+BucketList st_try_insert(char *name, SymbolKind symbolkind, ExpType type, int lineno) {
     int h = hash(name);
+    Scope scope = curr_scope();
+    BucketList *hashTable = scope->hashTable;
     BucketList l = hashTable[h];
     while ((l != NULL) && (strcmp(name, l->name) != 0))
         l = l->next;
-    if (l == NULL) /* variable not yet in table */
-    {
-        l = (BucketList) malloc(sizeof(struct BucketListRec));
+    if (l == NULL) { /* variable not yet in table */
+        l = (BucketList) malloc(sizeof(struct BucketListEntry));
         l->name = name;
-        l->lines = (LineList) malloc(sizeof(struct LineListRec));
+        l->symbolKind = symbolkind;
+        l->lines = (LineList) malloc(sizeof(struct LineListEntry));
         l->lines->lineno = lineno;
-        l->memloc = loc;
+        l->symbolKind = symbolkind;
+        if (symbolkind == SymbolFunc) {
+            l->type = Void;
+            l->returnType = type;
+            l->param_count = 0;
+        } else {
+            l->type = type;
+            l->returnType = type;
+        }
+
         l->lines->next = NULL;
+        l->memloc = scope->location;
+        scope->location++;
         l->next = hashTable[h];
         hashTable[h] = l;
-    } else /* found in table, so just add line number */
-    {
+    } else { /* found in table, so just add line number */
         LineList t = l->lines;
-        while (t->next != NULL) t = t->next;
-        t->next = (LineList) malloc(sizeof(struct LineListRec));
+        while (t->next != NULL)
+            t = t->next;
+        t->next = (LineList) malloc(sizeof(struct LineListEntry));
         t->next->lineno = lineno;
         t->next->next = NULL;
     }
-} /* st_insert */
+    return l;
+}
 
-/* Function st_lookup returns the memory 
- * location of a variable or -1 if not found
- */
-int st_lookup(char *name) {
+void st_entry_insert_line(BucketList entry, int lineno) {
+    if (entry == NULL) return;
+    LineList t = entry->lines;
+    while (t->next != NULL)
+        t = t->next;
+    t->next = (LineList) malloc(sizeof(struct LineListEntry));
+    t->next->lineno = lineno;
+    t->next->next = NULL;
+}
+
+BucketList st_lookup_current(char *name) {
     int h = hash(name);
+    Scope scope = curr_scope();
+    BucketList *hashTable = scope->hashTable;
     BucketList l = hashTable[h];
     while ((l != NULL) && (strcmp(name, l->name) != 0))
         l = l->next;
-    if (l == NULL) return -1;
-    else
-        return l->memloc;
+
+    return l;
 }
 
-/* Procedure printSymTab prints a formatted 
- * listing of the symbol table contents 
- * to the listing file
- */
-void printSymTab(FILE *listing) {
-    int i;
-    fprintf(listing, "Variable Name  Location   Line Numbers\n");
-    fprintf(listing, "-------------  --------   ------------\n");
-    for (i = 0; i < SYMTAB_SIZE; ++i) {
-        if (hashTable[i] != NULL) {
-            BucketList l = hashTable[i];
-            while (l != NULL) {
-                LineList t = l->lines;
-                fprintf(listing, "%-14s ", l->name);
-                fprintf(listing, "%-8d  ", l->memloc);
-                while (t != NULL) {
-                    fprintf(listing, "%4d ", t->lineno);
-                    t = t->next;
-                }
-                fprintf(listing, "\n");
-                l = l->next;
+BucketList st_lookup(char *name) {
+    int h = hash(name);
+    Scope scope = curr_scope();
+    while (scope != NULL) {
+        BucketList *hashTable = scope->hashTable;
+        BucketList l = hashTable[h];
+        while ((l != NULL) && (strcmp(name, l->name) != 0))
+            l = l->next;
+        if (l != NULL) {
+            return l;
+        }
+        scope = scope->parent;
+    }
+    return NULL; /* not found */
+}
+
+BucketList st_lookup_from(char *name, Scope scope) {
+    int h = hash(name);
+    while (scope != NULL) {
+        BucketList *hashTable = scope->hashTable;
+        BucketList l = hashTable[h];
+        while ((l != NULL) && (strcmp(name, l->name) != 0))
+            l = l->next;
+        if (l != NULL) {
+            return l;
+        }
+        scope = scope->parent;
+    }
+    return NULL; /* not found */
+}
+
+void printScope(FILE *listing, Scope scope) {
+    if (scope == NULL) return;
+    fprintf(listing, "Scope Name: %s, Depth: %d\n", scope->name, scope->depth);
+    fprintf(listing, "-----------------------------------------\n");
+    fprintf(listing, "Variable Name  Symbol Kind  Type       Location  Line Numbers\n");
+    fprintf(listing, "------------------------------------------------------------\n");
+
+    for (int i = 0; i < SYMTAB_SIZE; i++) {
+        BucketList l = scope->hashTable[i];
+        while (l != NULL) {
+            fprintf(listing, "%-14s", l->name);
+            switch (l->symbolKind) {
+                case SymbolVar:
+                    fprintf(listing, "%-13s", "Variable");
+                    break;
+                case SymbolFunc:
+                    fprintf(listing, "%-13s", "Function");
+                    break;
+                case SymbolParam:
+                    fprintf(listing, "%-13s", "Parameter");
+                    break;
             }
+            switch (l->type) {
+                case Void:
+                    fprintf(listing, "%-11s", "void");
+                    break;
+                case Integer:
+                    fprintf(listing, "%-11s", "int");
+                    break;
+                case IntegerArray:
+                    fprintf(listing, "%-11s", "int[]");
+                    break;
+            }
+            fprintf(listing, "%-9d", l->memloc);
+            LineList t = l->lines;
+            while (t != NULL) {
+                fprintf(listing, "%d ", t->lineno);
+                t = t->next;
+            }
+            fprintf(listing, "\n");
+            l = l->next;
         }
     }
-} /* printSymTab */
+    fprintf(listing, "\n");
+}
+
+static void printScopeRecursive(FILE *listing, Scope scope) {
+    if (scope == NULL) return;
+
+    printScope(listing, scope);
+
+    Scope child = scope->child;
+    while (child != NULL) {
+        printScopeRecursive(listing, child);
+        child = child->next_sibling;
+    }
+}
+
+void printScopeTree(FILE *listing) {
+    if (scope_global == NULL) return;
+
+    Scope current_scope = scope_global;
+
+    printScopeRecursive(listing, current_scope);
+}
+
+void printSymTab(FILE *listing) {
+    printScopeTree(listing);
+}
diff --git a/src/symtab.h b/src/symtab.h
index 26661a9..7d8d3f9 100644
--- a/src/symtab.h
+++ b/src/symtab.h
@@ -9,16 +9,23 @@
 
 #include "globals.h"
 
-/* SYMTAB_SIZE is the size of the hash table */
+/**
+ * it is the size of the hash table
+*/
 #define SYMTAB_SIZE 211
 
+#define MAX_SCOPE_DEPTH 32
+#define MAX_SCOPE_COUNT 1557
+
+#define MAX_PARAM_COUNT 13
+
 /* the list of line numbers of the source 
  * code in which a variable is referenced
  */
 typedef struct LineListEntry {
     int lineno;
     struct LineListEntry *next;
-} *LineList;
+} * LineList;
 
 /* The record in the bucket lists for
  * each variable, including name, 
@@ -29,61 +36,80 @@ typedef struct LineListEntry {
 typedef struct BucketListEntry {
     char *name;
     LineList lines;
+    SymbolKind symbolKind;
+    
     ExpType type;
+    ExpType param_types[MAX_PARAM_COUNT];
+    int param_count;
+    ExpType returnType;
+    
     int memloc; /* memory location for variable */
     struct BucketListEntry *next;
-} *BucketList;
+} * BucketList;
 
-typedef struct Scope {
+struct Scope {
     char *name;
     int depth;
+
     struct Scope *parent;
+    struct Scope *child;
+    struct Scope *child_last;
+    struct Scope *next_sibling;
+
+    int location;
     BucketList hashTable[SYMTAB_SIZE];
-} *Scope;
+};
 
-Scope scope_global;
+extern Scope scope_global;// no sibling no parent
 
-static Scope scope_list[SYMTAB_SIZE];
-static int size_list = 0;
+extern Scope scope_stack[MAX_SCOPE_DEPTH];
+extern int scope_stack_top;
 
-static Scope scope_stack[SYMTAB_SIZE];
-static int top_stack = -1;
+/**
+ * before using the symbol table, initialize the global scope
+ */
+void st_init(void);
 
 /**
  * create a new scope with given name
+ * @note it does not link parent or insert into stack/list
  * @param scope_name: name of the scope
  * @return the created scope
  */
 Scope scope_new(char *scope_name);
 /**
- * pop the current scope from the scope stack 
+ * pop the current scope from the scope stack
  */
 void pop_scope(void);
 /**
  * push a scope into the scope stack
+ * @note it does link the parent or siblings to construct tree
  * @param scope: the scope to be pushed
  */
 void push_scope(Scope scope);
 /**
- * insert a scope into the scope list
- */
-void insert_scope_to_list(Scope scope);
-/**
- * get the top of the scope stack
+ * get the top of the scope stack wit
  * @return the current scope or NULL if the stack is empty
  */
 Scope curr_scope(void);
 /**
- * insert a variable into the symbol table
- * or update a variable if it already exists
- * @param scope_name name of the scope
+ * insert a variable into the symbol table of the current scope
+ * or add a line number if it already exists
  * @param name name of the variable
+ * @param symbolkind kind of the symbol
  * @param type type of the variable
  * @param lineno line number of the variable
- * @param loc memory location of the variable
  * @return 0 if success, -1 if failure
  */
-int st_try_insert(char *name, ExpType type, int loc);
+BucketList st_try_insert(char *name, SymbolKind symbolkind, ExpType type, int lineno);
+
+/**
+ * insert a line number into the variable's line list
+ * @param entry the bucket list entry of the variable
+ * @param lineno the line number to be inserted
+ */
+void st_entry_insert_line(BucketList entry, int lineno);
+
 /**
  * lookup a variable in the current scope
  * @param name name of the variable to lookup
@@ -91,22 +117,24 @@ int st_try_insert(char *name, ExpType type, int loc);
  */
 BucketList st_lookup_current(char *name);
 /**
- * lookup a variable from the given scope to root
+ * lookup a variable from the top scope to root
  * @param name name of the variable to lookup
  * @return the bucket list entry of the variable or NULL if not found
  */
 BucketList st_lookup(char *name);
+
 /**
- * find a scope from the scope list
- * @param scope_name name of the scope to find
- * @return the scope or NULL if not found
- */
-Scope find_scope(char *scope_name);
-/** 
- * Procedure printSymTab prints a formatted 
- * listing of the symbol table contents 
- * to the listing file
+ * lookup a variable from the given scope to root
+ * @param name name of the variable to lookup
+ * @param scope the scope to start lookup from
+ * @return the bucket list entry of the variable or NULL if not found
  */
+BucketList st_lookup_from(char *name, Scope scope);
+
+void printScope(FILE *listing, Scope scope);
+
+void printScopeTree(FILE *listing);
+
 void printSymTab(FILE *listing);
 
 #endif
diff --git a/src/test.cm b/src/test.cm
new file mode 100644
index 0000000..b9d09e9
--- /dev/null
+++ b/src/test.cm
@@ -0,0 +1,13 @@
+int fib(int n) {
+    if (n <= 0) {
+        return 1;
+    } else {
+        return fib(n * fib(n - 1));
+    }
+}
+
+int main(void) {
+    int x;
+    x = fib(input());
+    output(x);
+}
\ No newline at end of file