爲什麼程序總是返回'false'？

Question

爲什麼此代碼總是返回'false'並且即使在輸入數字時也會激活goto？誰能幫幫我嗎？謝謝！

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

如果已經處理完畢，您只是忘了打破這種情況。 這種方式將處理案件，並處理true案件後處理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; 
} 

同樣的問題在這裏，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; 
}