Question

我的程序说＆＃34;错误：在＆＃39; bool＆＃39;＆＃34;之前预期的primary-expression;在主函数下的函数调用repeatOrNot (bool);上。这是为什么？

bool fiveOrNot(); 
void repeatOrNot (bool);

int main()
{
    fiveOrNot();
    repeatOrNot (bool);

    return 0;
}

bool fiveorNot()
{
    int number;
    cout << "Enter any number except for 5.\n";
    cin >> number;

    if(number == 5)
        return true;
    else
        return false;
}

void repeatOrNot(bool repeat)
{
    if(repeat == true)
        fiveorNot();
    else
        cout << ":(\n";
}

Answer 1

在C ++中。有所谓的形式参数和实际参数。在定义函数时，您正在处理形式参数，这意味着您应该只指定参数的类型，并且（如果您愿意）给它一些有意义的名称

void repeatOrNot(bool repeat)//<----"repeat" is a formal parameter. 
//You are not passing anything to the function, 
//you are just telling the compiler that this function accepts one argument 
//of a bool type.
{
    if(repeat == true)
        fiveorNot();
    else
        cout << ":(\n";
}

但是，当你调用一个函数时，你需要传递一个实际参数，即一个正确类型的变量。在您的情况下，您可能想要将调用的结果传递给fiveOrNot函数。你可以这样做：

bool isFive = fiveOrNot();
repeatOrNot (isFive);//<---This is an actual parameter.
//here you are really passing a variable to your function.

或者像这样：

repeatOrNot(fiveOrNot());//<--the result of the execution of "fiveOrNot" will be passed into "repeatOrNot"

预期的初级表达之前＆＃39; bool＆＃39;

1 个答案: