main.c

#include <stdio.h>
#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include "stack.h"

int check(char* expression){
	int i;
	for(i=0; i<= strlen(expression); i++){
		if(expression[i]=='(')
			{
				push('(');
			}
		else if(expression[i]==')')
			{
				is_empty();
				pop('(');
			}
		if(expression[i]=='{')
			{
				push('{');
			}
		else if(expression[i]=='}')
			{
				is_empty();
				pop('{');
			}
		if(expression[i]=='[')
			{
				push('[');
			}
		else if(expression[i]==']')
			{
				is_empty();
				pop('[');
			}
		}
	is_empty();
}

void test(void){
	assert(check(""));
	assert(check("()"));
	assert(check("()()"));
	assert(check("(())"));

	assert(check("{}"));
	assert(check("{}{}"));
	assert(check("{{}}"));

	assert(check("[]"));
	assert(check("[][]"));
	assert(check("[[]]"));

	assert(check("{[]}"));
	assert(check("([{}])"));
	assert(check("[{{{()}}}]"));
	assert(check("([{()}])"));

	assert(!check(")("));
	assert(!check("("));
	assert(!check(")"));

	assert(!check("}{"));
	assert(!check("{"));
	assert(!check("}"));

	assert(!check("]["));
	assert(!check("["));
	assert(!check("]"));
	
	assert(!check("(()"));
	assert(!check("())"));

	assert(!check("{{}"));
	assert(!check("{}}"));

	assert(!check("[[]"));
	assert(!check("[]]"));

	assert(!check("{)"));
	assert(!check("({])"));
	assert(!check("{[({)]}"));
	assert(!check("[({)]"));
	assert(!check("[(}]"));
	assert(!check("{{[}}"));

}

int main(void){
	test();
	clean_stack();
	return 0;
}

stack.c

#include <stdio.h>
#include <assert.h>

char values[100];
int index=0;

int push(char c){
	c = values[index++];
}

int pop(char c){
	if(index>0)
		{
			c = values[--index];
		}
	else if(index<0)
		{
			return 0;

		}
}		  

int is_empty(void){
	return index==0;
}

int clean_stack(void){
	index=0;
}

stack.h

#pragma once
int push(char c);
int pop(char c);
int is_empty(void);
int clean_stack();