如何在 C++ 中将用户输入验证为双精度值?
我如何检查输入是否真的是双精度的?
How would I check if the input is really a double?
double x;
while (1) {
cout << '>';
if (cin >> x) {
// valid number
break;
} else {
// not a valid number
cout << "Invalid Input! Please input a numerical value." << endl;
}
}
//do other stuff...
上面的代码无限输出Invalid Input! 语句，所以它不会提示另一个输入.我想提示输入，检查它是否合法......如果它是双重的，继续......如果它不是双重的，再次提示.
The above code infinitely outputs the Invalid Input! statement, so its not prompting for another input. I want to prompt for the input, check if it is legitimate... if its a double, go on... if it is NOT a double, prompt again.
有什么想法吗?
推荐答案
试试这个:
while (1) {
if (cin >> x) {
// valid number
break;
} else {
// not a valid number
cout << "Invalid Input! Please input a numerical value." << endl;
cin.clear();
while (cin.get() != '
') ; // empty loop
}
}
这基本上会清除错误状态，然后读取并丢弃上一行输入的所有内容.
This basically clears the error state, then reads and discards everything that was entered on the previous line.
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