为什么我的函数不返回一个字符串？

Question

我创建了一个函数（displayChoice）来生成一个随机数，然后创建另一个函数（getComputerChoice）来获取该数字并将该随机整数赋值给一个字符串。当我打印该字符串时，什么都不显示。我失去了为什么会发生这种情况。

#include <iostream> 
#include <limits> 
#include <ctime> 
#include <cstdlib> 
int getComputerChoice(); 
std::string displayChoice(int dChoice); 


int main() 
{ 

std::string comp = displayChoice(getComputerChoice()); 
std::cout << comp; 
} 
int getComputerChoice() 
{ 
    srand(time(NULL)); 
    int ranCompChoice = (rand() % 6) + 1; 
    return ranCompChoice; 
} 


std::string displayChoice(int dChoice) 
{ 
std::string ChoiceString; 
if (dChoice == 1) 
{ 
    ChoiceString == "rock"; 

} 
else if (dChoice == 2) 
{ 
    ChoiceString == "paper"; 
} 
else if (dChoice == 3) 
{ 
    ChoiceString == "scissors"; 
} 
else if (dChoice == 4) 
{ 
    ChoiceString == "lizard"; 
} 
else 
{ 
    ChoiceString == "Spock"; 
} 
    return ChoiceString; 
} 

Answer 1

您必须使用赋值运算符。

例如 ChoiceString = "Spock";