#include <stdio.h>
#define MAXSIZE 50
#define OK 1
#define ERROR 0
typedef struct
{
    char elem[MAXSIZE];
    int top;
}seqstack;
int judge()
{
    seqstack *x;
    x->top=-1;
    char ch;
    printf("请输入字符串:");
    ch=getchar();
    while(ch!='@'&&ch!='&')
    {
        x->top++;
        x->elem[x->top]=ch;
        ch=getchar();
    }
    ch=getchar();
    while(ch!='@')
    {
        if (ch==x->elem[x->top])
        {
            x->top--;
        }
        else
            return ERROR;
        if (x->top==-1)
            return OK;
        ch=getchar();
            
    }
}

int main()
{
    int a;
    a=judge();
    if (a==OK)
        printf("满足条件！！");
    else
        printf("不满足条件！！");
    return 0;

}


大家帮我看看这个程序，运行到x->top=-1;这句会出错，有什么问题吗？

哎呀，不好意思，了解啦，谢谢提醒！！！！！！！！！！

seqstack *x=(seqstack *)malloc(sizeof(seqstack));
这样就可以了