#include <stdio.h>
#define MAX 30

int main(int argc, char *argv[])
{
    int c,z=0,y=0,x=0,i=0;
    char a[MAX];

    while(((c=getchar())!='\n')&&((c=getchar())!=EOF)){
        switch(c)
        {
            case '{':
                z++;
                a[i]=c;
                i++;
                break;
            case '}':
                if(a[i-1]=='{'){
                    z--;
                    i--;
                }
                break;
            case '[':
                y++;
                a[i]=c;
                i++;
                break;
            case ']':
                if(a[i-1]=='['){
                    y--;
                    i--;
                }
                break;
            case '(':
                x++;
                a[i]=c;
                i++;
                break;
            case ')':
                if(a[i-1]=='('){
                    x--;
                    i--;
                }
                break;
            default:
                break;
        }
    }

    if(i==0){
        printf("OK");
    }else{
        printf("ERROR!");
    }
    return 0;
}
不能正确判断是否配对，比如我输入：P}，依然判断正确。
请问程序到底错在哪里呀。。

没人回答。。。
继续顶起。。。等待。。。