c++ - 双数程序意外值

Question

关于计划

该程序采用用户输入的数字并将该数字加倍输出。我创建了两个函数，一个收集数字 (getnumber)，另一个将数字加倍 (doublenumber)。该程序确实可以正常工作；但是，输出并不完全准确。

问题

输出只是部分正确。即用户输入 50，值加倍，输出应该是 100。相反，值输出为 100114。只有前几个数字似乎是我想要的。

源代码:

#include <iostream>

void doublenumber(int&);
void getnumber(int&);

int main() {

int value;

getnumber(value);
doublenumber(value);

std::cin.get();
std::cin.get();


return 0;
}

void doublenumber(int &refvar) {

    refvar*= 2;
    std::cout << "\nThe value you entered doubled is: " << refvar << '.\n';

}

void getnumber(int &userNum) {

    std::cout << "\nEnter a number to double: ";
    std::cin >> userNum;
}

Answer 1

std::cout << "\nThe value you entered doubled is: " << refvar << '.\n';
                                                                 ^^^^^
                                                                   |
                                                         multicharacter literal

它是一个多字 rune 字，类型为 int。

C++11 §2.13.2 Character literals

A character literal is one or more characters enclosed in single quotes, as in ’x’, optionally preceded by the letter L, as in L’x’. A character literal that does not begin with L is an ordinary character literal, also referred to as a narrow-character literal. An ordinary character literal that contains a single c-char has type char, with value equal to the numerical value of the encoding of the c-char in the execution character set. An ordinary character literal that contains more than one c-char is a multicharacter literal. A multicharacter literal has type int and implementation-defined value.

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