为什么会出现很多错误？

Question

#include <iostream>
int getValueFromUser()
{
    std::cout << "Enter An Integer !";
    int valueTyped{};
    std::cin >> valueTyped;
    return valueTyped;
}
void double(int valueToBeMultiplied)
{
    getValueFromUser();
    std::cout << valueToBeMultiplied << "Doubled Is :" << valueToBeMultiplied * 2;
}
int main()
{
    double(getValueFromUser()); // Use the () double on the return value of the getValueFromUser()
    return 0;
}

invalid combination of type specifiers 10
expected an identifier 10
expected a '}' 12
this declaration has no storage class or type specifier 13
expected a ';' 13
expected a declaration 14

Error   C2556   'double getValueFromUser(void)': overloaded function differs only by return type from 'int getValueFromUser(void) 16    

严重性代码描述项目文件行抑制状态 错误C2371'getValueFromUser'：重新定义；不同的基本类型16

Answer 1

核心问题是double是C ++中的关键字。 double是fundamental type，代表一个double-precision floating-point数字。不能用作函数名称。尝试重命名该功能：

void double_it(int valueToBeMultiplied)
{
    getValueFromUser();
    std::cout << valueToBeMultiplied << "Doubled Is :" << valueToBeMultiplied * 2;
}