Stack application (balancer)

explain ： Is based on the previous chapter ,C Language realizes the basic functions of stack .
Stack code

symbol_match.h

#ifndef __SYMBOL_MATCH_C__
#define __SYMBOL_MATCH_C__

extern int scanner(const char *code);

#endif

symbol_match.c

#include "symbol_match.h"
#include "link_stack.h"


static int is_left(char c)
{
    
    int ret = 0;
    switch(c)
    {
    
    case '<':
    case '(':
    case '[':
    case '{':
    case '\'':
    case '\"':
        ret = 1;
        break;
    default:
        ret = 0;
        break;
    }
    return ret;
}

static int is_right(char c)
{
    
    int ret = 0;

    switch(c)
    {
    
    case '>':
    case ')':
    case ']':
    case '}':
    case '\'':
    case '\"':
        ret = 1;
        break;
    default:
        ret = 0;
        break;
    }

    return ret;
}

static int match(char left, char right)
{
    
    int ret = 0;

    switch(left)
    {
    
    case '<':
        ret = (right == '>');
        break;
    case '(':
        ret = (right == ')');
        break;
    case '[':
        ret = (right == ']');
        break;
    case '{':
        ret = (right == '}');
        break;
    case '\'':
        ret = (right == '\'');
        break;
    case '\"':
        ret = (right == '\"');
        break;
    default:
        ret = 0;
        break;
    }

    return ret;
}


int scanner(const char *code)
{
    
    int ret = 0;
    int i=0;
    char *c;
    link_stack *head;
    head = link_stack_create();

    while(code[i] != '\0')
    {
    
// printf("%c",code[i]);
        if ( is_left(code[i]))
        {
    
            link_stack_push(head,(void*)&code[i]);
        }
        if ( is_right(code[i]))
        {
    
            c = link_stack_pop(head);
            if (c==NULL || !match(c[0],code[i]))
            {
    
                printf("%c does not match!\n", code[i]);
                ret = 0;
                break;
            }
        }
        i++;
    }

    if ( 0==link_stack_size(head) && code[i]=='\0')
    {
    
        printf("Succeed!\n");
        ret = 1;
    } else
    {
    
        printf("Invalid code!\n");
        ret = 0;
    }

    link_stack_destroy(head);

	return ret;
}

Test code

#include "stdio.h"
#include "stdint.h"
#include "symbol_match.h"



int main(void)
{
    
//#define BUF_SIZE 10
// int i;
// int buf[BUF_SIZE];
// int *int32_tmp;

	//const char* code = "#include <stdio.h> int main() { int a[5][5]; int (*p)[4]; p = a[0]; printf(\"%d\\n\", &p[3][3] - &a[3][3]); return 0; }";
    const char* code = "{}[][]asdggggggggg<>()hhhhhhhh[][iiiiiiiiiiiii]";
		
	printf("hello\n");
	
	scanner(code);
   
}