PAT甲级1108题（平均数）

1.题目介绍

2.考察点，难度

字符串处理类，字符串判断，难度中

3.解题代码

#include<iostream>
#include<cstring>
using namespace std;

int main(){

    int n, k = 0;
    scanf("%d", &n);
    char s[50], t[50];
    double num, sum = 0.0;

    for (int i = 0; i < n; i++){
        scanf("%s", s);
        sscanf(s, "%lf", &num);     // 从s字符串中读进与指定格式相符的数据
        sprintf(t, "%.2f", num);    // 字符串格式化命令，主要功能是把格式化的数据写入某个字符串中
        bool islegal = true;
        for (int j = 0; j < strlen(s); j++)
            if (s[j] != t[j]) islegal = false;
        if (islegal && num >= -1000 && num <= 1000){
            k++;
            sum += num;
        }
        else printf("ERROR: %s is not a legal number\n", s);
    }
    if (!k) printf("The average of 0 numbers is Undefined\n");
    else if (k == 1) printf("The average of 1 number is %.2f\n", sum);
    else printf("The average of %d numbers is %.2f\n", k, sum / k);

    return 0;
}

4.原题地址

https://pintia.cn/problem-sets/994805342720868352/problems/994805360777347072