Create balanced & unbalanced parenthesis

[aditi-disaster]

#include<stdio.h>
#include<string.h>
#define SIZE 20
char STACK[SIZE];
int top=-1;
void push(char item)
{
if(top==SIZE-1)
printf("\nSTACK IS OVERFLOW");
else
{
top++;
STACK[top]=item;
}
}
void pop()
{
if(top==-1)
printf("\nunderflow");
else
top--;
}
int main(void)
{
char exp[SIZE];
int len,i;
printf("\nenter the expression");
scanf("%s",exp);
len=strlen(exp);
for(i=0;i<len;i++)
{

	if(exp[i]=='(' || exp[i]=='{' || exp[i]=='[')
	{
		push(exp[i]);
		continue;
	}
	else if(exp[i]==')' || exp[i]=='}' || exp[i]==']')
	{
		if(exp[i]==')')
		{
			if(STACK[top]=='(')
			{
				pop();
			}
			else
			{
				printf("\nUNBALANCED PARENTHESIS");
				return 0;
			}
		}
		else if(exp[i]=='}')
		{
			if(STACK[top]=='{')
			{
				pop();
			}
			else
			{
				printf("\nUNBALANCED PARENTHESIS");
				return 0;
			}
		}
			else if(exp[i]==']')
			{
				if(STACK[top]=='[')
				{
					pop();
				}
				else
				{
					printf("\nUNBALANCED PARENTHESIS");
					return 0;
				}
			}
		}
	}

if(top!=-1)
printf("\nUNBALANCED PARENTHESIS");
else
printf("\nBALANCED PARENTHESIS");
return 0;

}