【刷题-PAT】A1108 Finding Average （20 分）

1108 Finding Average （20 分）

The basic task is simple: given N real numbers, you are supposed to calculate their average. But what makes it complicated is that some of the input numbers might not be legal. A legal input is a real number in [−1000,1000] and is accurate up to no more than 2 decimal places. When you calculate the average, those illegal numbers must not be counted in.

Input Specification:

Each input file contains one test case. For each case, the first line gives a positive integer N (≤100). Then N numbers are given in the next line, separated by one space.

Output Specification:

For each illegal input number, print in a line ERROR: X is not a legal number where X is the input. Then finally print in a line the result: The average of K numbers is Y where Kis the number of legal inputs and Y is their average, accurate to 2 decimal places. In case the average cannot be calculated, output Undefined instead of Y. In case K is only 1, output The average of 1 number is Y instead.

Sample Input 1:

7

5 -3.2 aaa 9999 2.3.4 7.123 2.35

Sample Output 1:

ERROR: aaa is not a legal number

ERROR: 9999 is not a legal number

ERROR: 2.3.4 is not a legal number

ERROR: 7.123 is not a legal number

The average of 3 numbers is 1.38

Sample Input 2:

2

aaa -9999

Sample Output 2:

ERROR: aaa is not a legal number

ERROR: -9999 is not a legal number

The average of 0 numbers is Undefined

分析：使用sscanf()和sprintf()函数即可

#include<iostream>

#include<cstdio>

#include<cstring>

#include<vector>

#include<string>

#include<unordered_map>

#include<set>

#include<queue>

#include<algorithm>

#include<cmath>

using namespace std;

int main(){

    #ifdef ONLINE_JUDGE

    #else

    freopen("input.txt", "r", stdin);

    #endif // ONLINE_JUDGE

    int n = 0;

    scanf("%d", &n);

    int cnt = 0;

    double sum = 0, num;

    for(int i = 0; i < n; ++i){

        char str[100], t[100];

        scanf("%s", str);

        sscanf(str, "%lf", &num);

        sprintf(t, "%.2f", num);

        bool flag = true;

        //写入失败时，写入的地方存的还是之前的内容，所以要比较

        for(int i = 0; i < strlen(str); ++i){

            if(str[i] != t[i])flag = false;

        }

        if(flag == false || abs(num) > 1000){

            printf("ERROR: %s is not a legal number\n", str);

        }else{

            cnt++;

            sum += num;

        }

    }

    if(cnt == 0){

        printf("The average of 0 numbers is Undefined\n");

    }else if(cnt == 1){

        printf("The average of 1 number is %.2lf\n", sum);

    }else{

        printf("The average of %d numbers is %.2lf\n", cnt, sum / cnt);

    }

    return 0;

}

巴特西

【刷题-PAT】A1108 Finding Average （20 分）

最新文章

热门文章