Question

这是什么意思？我的程序是这样的:(注意：出现错误的行是在案例2之前的行。）

case 1:
{
cout<< "C * H * E * M * I * S * T * R * Y \n\n";
cout<< "1) What is the valence electron configuration of Selenium (Se)?\n\n";
cout<< "\na) 1s2 2s2 2p6 3s2\n\n";
cout<< "\nb) 1s2 2s2 2p2\n\n";
cout<< "\nc)4s2 4p4\n\n";
cout<< "\nd) 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p5\n\n";
cout<< "Enter your answer:\n";
cin>> answer;

if (answer == 'c')
{
    cout<<"Your answer is correct. Please press the enter key to proceed to the next question.\n\n";
}
else
    cout<< "The correct answer is C. Please press the enter key to proceed to the next question.\n\n";

getch ();
}

getch ();
cout<< "2) Which element yields the biggest atomic radius?\n\n";
cout<< "\na) Ca\n\n";
cout<< "\nb) Xe\n\n";
cout<< "\nc) B\n\n";
cout<< "\nd) Cs\n\n";
cout<< "Enter your answer:\n";
cin>> answer;
if (answer == 'd')
{
    cout<< "Your answer is correct. Please press the enter key to proceed to the next question.\n\n";
}
else
    cout<< "The correct answer is D. Please press the enter key to proceed to the next question.\n\n";

getch ();
}

cout<< "3) Name the ionic compound K2 Cr2 O7\n\n";
cout<< "\na) potassium chloride\n\n";
cout<< "\nb) potassium carbonate\n\n";
cout<< "\nc) potassium chromite\n\n";
cout<< "\nd) potassium chromate\n\n";
cout<< "Enter your answer:\n";
cin>> answer;
if (answer == 'd')
{
    cout<< "Your answer is correct. Please press the enter key to proceed to the next question.\n\n";
}
else
    cout<< "The correct answer is D. Please press the enter key to proceed to the next question.\n\n";


getch ();
}
}
case 2:
{
cout<< "G * E * O * M * E * T * R * Y \n\n";

标题中提到的错误是我在开头段落中注明的行expected declaration before '}' token。

Answer 1

我想你想要这个：

if (answer == 'd')
{
    cout<< "Your answer is correct. Please press the enter key to proceed to the next question.\n\n";
}
else
    cout<< "The correct answer is D. Please press the enter key to proceed to the next question.\n\n";


getch ();
}
}

看起来像这样：

if (answer == 'd')
{
    cout<< "Your answer is correct. Please press the enter key to proceed to the next question.\n\n";
} else {
    cout<< "The correct answer is D. Please press the enter key to proceed to the next question.\n\n";
    getch ();
}

您似乎在else之后立即忘记了您的范围。

Answer 2

在case之前有两个}。相应的{是什么？特别是最后else看起来有些孤独。

Answer 3

在我重新格式化您的代码后，它会在网站上显示出来，错误非常明显。

我建议，当你在if子句周围使用括号时，也要在else子句周围使用它们：

 if (foo) {
     /* ... */
 } else {
     /* ... */
 }

如果两个案例只是一个陈述，那么离开括号是很好的。虽然如果只有一个需要，但没有要求在两个子句中放置括号，我发现if语句周围有很多错误，只有一个路径括号。这令人惊讶。：）

另外请注意，具有括号匹配功能的文本编辑器将是一个巨大的帮助。许多编辑器将突出显示未正确嵌套的括号，有些编辑器提供了快速跳转它们的关键。（在vi和克隆中，%键会在()，{}，[]和<>对之间反弹。非常方便。）< / p>

Answer 4

在每次演出后，你似乎都有一个超级的“}”：

 getch ();
 }
^^^

DEV C ++错误：'}'令牌之前的预期声明

4 个答案: