중위연산식을 후위연산식으로 바꿔서 출력하기

#include [stdio.h] // 꺽쇠가 자꾸 사라져서 []로 했습니다.
#include [stdlib.h] 
#include [string.h] 
 
typedef int element;
 
typedef struct stackNode {			
	element data; 
	struct stackNode *link; 
}stackNode; 
 
stackNode* top;
 
void push(element item) 
{	
	stackNode* temp=(stackNode *)malloc(sizeof(stackNode));
	temp->data = item; 
	temp->link = top;	
	top = temp; 
} 
 
element pop() 
{ 
	element item;
	stackNode* temp=top;
 
	if(top == NULL) { 	 
		printf("\n\n Stack is empty !\n");	 
		return 0; 
	} 
	else { 
		item = temp->data;	
		top = temp->link;	 
		free(temp);				
		return item; 
	} 
} 
 
element peek() 
{	
	element item; 
	if(top == NULL) {		 
		printf("\n\n Stack is empty !\n");	 
		return 0;	 
	} 
	else { 
		item = top->data; 
		return item; 
	} 
} 
 
void del() 
{  
	stackNode* temp; 
	if(top == NULL) {		
		printf("\n\n Stack is empty !\n");	
 
	} 
	else { 
		temp = top;	
		top = top->link;	 
		free(temp); 
	} 
} 
 
void printStack()
{
	stackNode* p=top;
	printf("\n STACK [ ");
	while(p){
		printf("%d ",p->data);
		p = p->link;
	}
	printf("] ");
}
 
element evalPostfix(char *exp)
{
	int opr1, opr2, value, i=0;
	int length = strlen(exp);
	char symbol;
	top = NULL;
 
	for(i=0; i<length; i++){
		symbol = exp[i];
		if(symbol != '+' && symbol != '-' && symbol != '*' && symbol != '/'){
			value = symbol - '0';
			push(value);
		}
		else{
			opr2 = pop();
			opr1 = pop();
			switch(symbol){
			case '+' : push(opr1 + opr2); break;
			case '-' : push(opr1 - opr2); break;
			case '*' : push(opr1 * opr2); break;
			case '/' : push(opr1 / opr2); break;
			}
		}
	}
	return pop();
}
 
void main(void) 
{ 		
	int result;
	char* express = "35*62/-";
	printf("후위표기식 : %s", express);
 
	result = evalPostfix(express);
	printf("\n\n 연산결과 => %d", result);
 
	getchar();
}