如何退出循环？ [英] How do I exit the loop?

问题描述

我创建了一个C ++程序来计算学生的平均成绩。第一部分可以工作，但是当我输入done退出时，我的程序会经历一个无限循环并且不会停止生成数字。



这是我的代码：

I created a C++ program to compute a student's average grade. The first part works, but when I type "done" to exit, my program goes through an infinite loop and won't stop producing numbers.

Here is my code:

#include <iostream>

using namespace std ;

void studentGrade (string) ;

int main ()
{
	string name ;
	int scoreOne, scoreTwo, scoreThree, scoreFour, scoreFive, scoreSix, scoreSeven, scoreEight, scoreNine, scoreTen ;
	float average = 0 ;			//stores the average of all grades
	float total = 0 ;			//stores sum of grades
	char letterGrade ;			//stores the final letter grade of student
	name = "zero" ;
	studentGrade (name) ;
	
}
void studentGrade (string name)
{
	int scoreOne, scoreTwo, scoreThree, scoreFour, scoreFive, scoreSix, scoreSeven, scoreEight, scoreNine, scoreTen ;
	char letterGrade ;
	float average = 0 ;
	float total = 0 ;
	while (name != "done")
	{
		cout << "Enter student's name." << endl ;
		getline (cin, name) ;
		cin.ignore () ;
		if (name != "done")
		{
			cout << "Enter " << name << "'s 10 test scores." ;
			cin >> scoreOne >> scoreTwo >> scoreThree >> scoreFour >> scoreFive >> scoreSix >> scoreSeven >> scoreEight >> scoreNine >> scoreTen ;
			total = scoreOne + scoreTwo + scoreThree + scoreFour + scoreFive + scoreSix + scoreSeven + scoreEight + scoreNine + scoreTen ;
			average = total / 10 ;
			if (average > 89.5)
				letterGrade = 'A' ;
			else if (average > 79.5)
				letterGrade = 'B' ;
			else if (average > 69.5)
				letterGrade = 'C' ;
			else if (average > 59.5)
				letterGrade = 'D' ;
			else
			letterGrade = 'F' ;
		cout << "Student's name: " << name << endl ;
		cout << "Average Grade: " << average << endl ;
		cout << "Letter Grade: " << letterGrade << endl ;
		name = "zero" ;
		}
		else
			cout << "All student's done." << endl ;
	}
	cout << "All student's done." << endl ;
}

我的尝试：



当我输入名称时，程序正常工作，但当我输入完成退出时，它不会。我只是想知道我是否错过了退出循环或者我没有做正确的事情。感谢您的帮助！

What I have tried:

When I type names, the program works properly, but when I enter "done" to exit, it doesn't. I was just wondering if I am missing something to exit the loop or if I didn't do something right. Thank you for helping!

推荐答案

Quote：

while（name！=完成）

{

cout<< 输入学生的姓名。 << endl;

getline（cin，name）;

cin.ignore（）;

if（name！=done）

{

cout<< 输入<<名称<< 有10个考试成绩。 ;

cin>> scoreOne>>得分2>>得分三>> scoreFour>> scoreFive>> scoreSix>>得分>> scoreEight>> scoreNine>>得分10分;

总计=得分一分+得分两分+得分三分+得分四分+得分五分+得分六分+得分七分+得分八分数+分数十分;

while (name != "done")
{
cout << "Enter student's name." << endl ;
getline (cin, name) ;
cin.ignore () ;
if (name != "done")
{
cout << "Enter " << name << "'s 10 test scores." ;
cin >> scoreOne >> scoreTwo >> scoreThree >> scoreFour >> scoreFive >> scoreSix >> scoreSeven >> scoreEight >> scoreNine >> scoreTen ;
total = scoreOne + scoreTwo + scoreThree + scoreFour + scoreFive + scoreSix + scoreSeven + scoreEight + scoreNine + scoreTen ;

移动 cin.ignore（）; 声明，以获取

Move the cin.ignore(); statement, in order to obtain

while (name != "done")
	{
		cout << "Enter student's name." << endl ;
		getline (cin, name) ;
		
		if (name != "done")
		{
			cout << "Enter " << name << "'s 10 test scores." ;
			cin >> scoreOne >> scoreTwo >> scoreThree >> scoreFour >> scoreFive >> scoreSix >> scoreSeven >> scoreEight >> scoreNine >> scoreTen ;
            cin.ignore (); // <--- moved here
			total = scoreOne + scoreTwo + scoreThree + scoreFour + scoreFive + scoreSix + scoreSeven + scoreEight + scoreNine + scoreTen ;

尝试将循环更改为以下内容：

Try changing the loops to something like this :

while( true )
{
    cout << "Enter student's name." << endl;
    getline( cin, name );
    cin.ignore();
    if( name == "done" )
        break;
    // continue logic here
}

只需添加

break

您认为需要停止循环。

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