题解 | #【模板】栈#

#include <stdio.h>
#include <string.h>
// #include <stdlib.h>

#define MAXSIZE 100000

typedef struct{
    int stack[MAXSIZE];
    int top;
}Stack, *LStack;

void push(LStack s, int x){
    s->stack[s->top++] = x;
}

void pop(LStack s){
    if(!(s->top)){
        printf("error\n");
    }
    else {
        printf("%d\n", s->stack[--s->top]);
    }
}

void top(LStack s){
    if(!(s->top)){
        printf("error\n");
    }
    else {
        printf("%d\n", s->stack[s->top - 1]);
    }
}

int main() {
    int n;
    scanf("%d", &n);

    Stack stack;
    LStack lstack = &stack;
    stack.top = 0;

    char operation[5];
    int nums;
    for (int i = 0; i < n; i++) {
        scanf("%s %d", operation, &nums);
        if (!(strcmp(operation, "push"))) {
            push(lstack, nums);
        }
        else if (!(strcmp(operation, "pop"))) {
            pop(lstack);
        }
        else if (!(strcmp(operation, "top"))) {
            top(lstack);
        }
    }

    return 0;
}