题解 | #学生基本信息输入输出#

#include <iostream>
#include <iomanip>
#include <math.h>
using namespace std;
//计算平方

//小数点保留bits位，并对后一位进行四舍五入
double Round(double number, int bits)  // 1.1   1.11  1.111
{
    //求个位数字进行判断
    double oldNumber = number;  //1.1
    for(int i = 0; i <= bits; i++)
    {
        oldNumber *= 10;
    }
    int newNumber = oldNumber;  //1100
    int x = newNumber % 10; //1
    double ret = 0.0;
    if(x >= 5 )
    {
        return ret = (newNumber + 5) / pow(10, bits+1);
    }else {
    
        return number;
    
    }
}
int main() {
    unsigned long id;
    float xa , xb , xc ;
    char c;  //读掉字符
    cin >> id >> c >> xa >> c >> xb >> c >> xc;
    //cout.precision(2);
    cout << fixed;
    cout << setprecision(2);
    
    cout << "The each subject score of No. " << id << " is " << Round(xa, 2) << ", " << Round(xb, 2) << ", "<< Round(xc, 2) << "." << endl;

    

    return 0;
}
// 64 位输出请用 printf("%lld")