Question

C ++初学者。我正在尝试复制这个输出，我几乎就在那里，但我在最后一部分（测验百分比）遇到了麻烦。

 Example    output:
 Welcome to our math quiz program! Please enter the answers to the
 following questions:
 5! = 5
 (2^(2^(2^2))) = 65536
 3 * (4 + 8) / ((4 * 2) / (5 – 1)) = 18
 3 + 2 + 1 + 2 + 3 = 11
 Number of correct answers: 3
 Number of incorrect answers: 1
 Quiz percentage: 75%

到目前为止，这是我的代码：

int problem4() {
int numCorrect = 0;
int numIncorrect = 0;
int possibleCorrect = 4;

int correctAnswerOne = 120;
int correctAnswerTwo = 65536;
int correctAnswerThree = 18;
int correctAnswerFour = 11;

int guessOne;
int guessTwo;
int guessThree;
int guessFour;

cout << "*** Start of problem 4 ***" << endl;
cout << "Welcome to our math quiz program!" << endl;
cout << "Please enter the answers to the following questions: " << endl;
cout << "5! = ";
cin >> guessOne;
cout << "(2^(2^(2^2))) = ";
cin >> guessTwo;
cout << "3 * (4 + 8) / ((4 * 2) / (5 - 1)) = ";
cin >> guessThree;
cout << "3 + 2 + 1 + 2 + 3 = ";
cin >> guessFour;

switch (guessOne) {
    case 120:
        numCorrect++;
        break;
    default:
        numIncorrect++;
}

switch (guessTwo) {
case 65536:
    numCorrect++;
    break;
default:
    numIncorrect++;
}

switch (guessThree) {
case 18:
    numCorrect++;
    break;
default:
    numIncorrect++;
}

switch (guessFour) {
case 11:
    numCorrect++;
    break;
default:
    numIncorrect++;
}

cout << "Number of correct answers: " << numCorrect << endl;
cout << "Number of incorrect answers: " << numIncorrect << endl;
cout << "Quiz percentage: " << (numCorrect / possibleCorrect) * 100 << "%" << endl;
cout << endl;

return 0;
}

似乎当我正确地回答所有问题时，我得到的是100％，但是，当我得到任何东西（只有1,2或3个正确）时，我最终得到0％的结果。我以为我正在正确地进行百分比计算，但输出是另外建议的。任何人都能指出我正确的方向吗？感谢。

编辑：为交换机添加了中断（但不是问题的根源）。

Answer 1

您的交换机缺少Break语句。

另外，您需要将结果类型转换为float，因为所有变量都是整数。我建议你使用：

float perc;

perc = (numCorrect/possibleCorrect)*100;

Answer 2

如果你切换你需要一个休息时间，然后先乘以100.0来隐式地将第一个表达式提升为double然后除以：

int problem4() {
int numCorrect = 0;
int numIncorrect = 0;
int possibleCorrect = 4;

int correctAnswerOne = 120;
int correctAnswerTwo = 65536;
int correctAnswerThree = 18;
int correctAnswerFour = 11;

int guessOne;
int guessTwo;
int guessThree;
int guessFour;

cout << "*** Start of problem 4 ***" << endl;
cout << "Welcome to our math quiz program!" << endl;
cout << "Please enter the answers to the following questions: " << endl;
cout << "5! = ";
cin >> guessOne;
cout << "(2^(2^(2^2))) = ";
cin >> guessTwo;
cout << "3 * (4 + 8) / ((4 * 2) / (5 - 1)) = ";
cin >> guessThree;
cout << "3 + 2 + 1 + 2 + 3 = ";
cin >> guessFour;

switch (guessOne) {
case 120:
    numCorrect++;
    break;
default:
    numIncorrect++;
}

switch (guessTwo) {
case 65536:
    numCorrect++;
    break;
default:
    numIncorrect++;
}

switch (guessThree) {
case 18:
    numCorrect++;
    break;
default:
    numIncorrect++;
}

switch (guessFour) {
case 11:
    numCorrect++;
    break;
default:
    numIncorrect++;
}

cout << "Number of correct answers: " << numCorrect << endl;
cout << "Number of incorrect answers: " << numIncorrect << endl;
cout << "Quiz percentage: " << (numCorrect * 100.0 / possibleCorrect) << "%" << endl;
cout << endl;

return 0;
}

为此目的，一个简单的if / else更容易阅读：

int problem4() {
int numCorrect = 0;
int numIncorrect = 0;
int possibleCorrect = 4;

int correctAnswerOne = 120;
int correctAnswerTwo = 65536;
int correctAnswerThree = 18;
int correctAnswerFour = 11;

int guessOne;
int guessTwo;
int guessThree;
int guessFour;

cout << "*** Start of problem 4 ***" << endl;
cout << "Welcome to our math quiz program!" << endl;
cout << "Please enter the answers to the following questions: " << endl;
cout << "5! = ";
cin >> guessOne;
cout << "(2^(2^(2^2))) = ";
cin >> guessTwo;
cout << "3 * (4 + 8) / ((4 * 2) / (5 - 1)) = ";
cin >> guessThree;
cout << "3 + 2 + 1 + 2 + 3 = ";
cin >> guessFour;
if( guessOne == 120 ) ++numCorrect; else ++numIncorrect;
if( guessTwo == 65536 ) ++numCorrect; else ++numIncorrect;
if( guessThree == 18 ) ++numCorrect; else ++numIncorrect;
if( guessFour == 11 ) ++numCorrect; else ++numIncorrect;

cout << "Number of correct answers: " << numCorrect << endl;
cout << "Number of incorrect answers: " << numIncorrect << endl;
cout << "Quiz percentage: " << (numCorrect * 100.0 / possibleCorrect) << "%" << endl;
cout << endl;

return 0;
}

无法获得C ++中的百分比

2 个答案: