Question

我玩了一个多星期都没有成功。现在它的运行方式将跳过while循环的第一次迭代的第一个字母。如果删除cin.ignore()，则下面的代码不起作用。

#include <iostream>
#include <iomanip>
#include <string>

using namespace std;

int main(){
    cout << fixed << setprecision(2);
    float gpaTot = 0, gpa, clasNum;
    int creds;
    string clas, cont = "Yes", grade;

    while (cont == "Yes"){
        cin.ignore();
        cout <<"Enter a course name: ";
        getline(cin, clas);
        cout << clas << endl << "Enter number of credits: ";
        cin >> creds;
        cout << creds << endl << "Enter your grade (A, B, C, D, F): ";
        cin >> grade;
        cout << grade << endl << "Continue ('Yes' or 'No')? ";
        cin >> cont;
        cout << cont << endl;
    }

Answer 1

将cin.ignore()调用移至循环末尾。

while (cont == "Yes"){
    cout <<"Enter a course name: ";
    getline(cin, clas);
    cout << clas << endl << "Enter number of credits: ";
    cin >> creds;
    cout << creds << endl << "Enter your grade (A, B, C, D, F): ";
    cin >> grade;
    cout << grade << endl << "Continue ('Yes' or 'No')? ";
    cin >> cont;
    cout << cont << endl;
    cin.ignore();
}

这样，对getline的第一次调用不会跳过字母。后续调用也可以正常进行，因为cin >> cont;读取并丢弃了cin.ignore()行中剩余的换行符。

循环内缺少首字母的C ++ getline。没有cin.ignore不能工作吗？

1 个答案: