C语言，样例过了但是不知道为什么全WA（第一个测试点就是样例

#include <stdio.h>
#include <math.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>

int iscalcu(char c) {
    return ((c=='+')||(c=='-')||(c=='*')||(c=='/'));
}

int main() {
    int num[1000] = {0}, top_loc = -1;
    int temp = 0;
    char s[1000];
    memset(s, 0, 1000);
    int i, j;
    fgets(s, 1000, stdin);
    int l = strlen(s);
    while ( s[l] == '\r' || s[l] == '\n') s[l--] = '\0';
    for(i = 0; s[i] != '@'; i++) {
        if(isdigit(s[i])) {
            temp = 0;
            while (s[i] != '.') {
                temp = temp*10 + s[i] - '0';
                i++;
            }
            num[++top_loc] = temp;
        }
        if(iscalcu(s[i])) {
            if(s[i] == '+') {
                num[top_loc-1] = num[top_loc-1] + num[top_loc--];
            }
            if(s[i] == '-') {
                num[top_loc-1] = num[top_loc-1]-num[top_loc--];
            }
            if(s[i] == '*') {
                num[top_loc-1]=num[top_loc-1]*num[top_loc--];
            }
            if(s[i] == '/') {
                num[top_loc-1]=num[top_loc-1]/num[top_loc--];
            }
        }
    }
    printf("%d\n",num[0]);

    return 0;
}