题解 | #【模板】栈#

C语言的解法如下：

#include<stdlib.h>
#include<string.h>
#define MAX 100000
typedef struct Stack{
    int a[MAX];
    int topp;
}*LStack;
void inistack(LStack s){
    s->topp=0;
}
void push(LStack s,int x){
    s->a[s->topp]=x;
    s->topp++;
}
int pop(LStack s){
    if(s->topp==0){
        return -1;
    }
    return s->a[--s->topp];
    
}
int top(LStack s){
    if(s->topp==0){
        return -1;
    }
    int num=s->a[--s->topp];
    s->topp++;
    return num;
}
int main(){
    LStack s=(LStack)malloc(sizeof(struct Stack));
    inistack(s);
    int n=0;
    scanf("%d",&n);
    while(n--){
        char *str=(char*)malloc(6*sizeof(char));
        
        scanf("%s",str);
        if(!strcmp(str,"push")){
            int num=0;
            scanf("%d",&num);
            push(s,num);
        }
        if(!strcmp(str,"pop")){
            int num1=pop(s);
            if(num1==-1){
				printf("error\n");
				continue;
			}
            printf("%d\n",num1);
        }
        if(!strcmp(str,"top")){
            int num2=top(s);
            if(num2==-1){
				printf("error\n");
				continue;
			}
            printf("%d\n",num2);
        }
        
    }
    
    
    
    
    return 0;
}