为什么程序总是返回'false'？

Question

为什么此代码总是返回'false'并且即使在输入数字时也会激活goto？谁能帮帮我吗？谢谢！

char userValue = '4'; 
auto h = true; 
tryAgain: 
std::cout << "Please type a digit: "; 
std::cin >> userValue; 

switch (userValue) { 
case '0': 
case '1': 
case '2': 
case '3': 
case '4': 
case '5': 
case '6': 
case '7': 
case '8': 
case '9': 
    h = true; 
default: 
    h = false; 
} 

switch (h) { 
case true: 
    std::cout << "This character is a digit."; 
case false: 
    std::cout << "Wrong! Try again!" << std::endl; 
    goto tryAgain; 
} 

Answer 1

如果已经处理完毕，您只是忘了打破这种情况。 这种方式将处理案件，并处理true案件后处理false案件。

switch (h) { 
case true: 
    std::cout << "This character is a digit."; 
break; 
case false: 
    std::cout << "Wrong! Try again!" << std::endl; 
    goto tryAgain; 

    //not necessarily needed because goto leaves the scope anyway. 
    //break; 
} 

同样的问题在这里，打破，如果你wan't停止下通：

switch (userValue) { 
case '0': 
case '1': 
case '2': 
case '3': 
case '4': 
case '5': 
case '6': 
case '7': 
case '8': 
case '9': 
    h = true; 
    break; 

default: 
    h = false; 
    break; 
}