更改main中变量的值以用于其他函数(c ++)

#include<iostream>

int myVar;

void otherFunction() {
    std::cout << "myVar in otherFunction: " << myVar<< std::endl;
}

int main() {
    myVar = 10;
    std::cout << "myVar in main: " << myVar<< std::endl;
    otherFunction();
    return 0;
}

#include<iostream>

void otherFunction(int var) {
    std::cout << "myVar in otherFunction: "<< var<< std::endl;
}

int main() {
    int myVar = 10;
    std::cout << "myVar in main: " << myVar<< std::endl;
    otherFunction(myVar);
    return 0;
}

#include<iostream>

void otherFunction(int* var) {
    std::cout << "myVar in otherFunction: " << *var<< std::endl;
    *var = 20;
}

int main() {
    int myVar = 10;
    std::cout << "myVar in main: " << myVar<< std::endl;
    otherFunction(&myVar);
    std::cout << "myVar in main after otherFunction: " << myVar<< std::endl;
    return 0;
}

#include<iostream>

void otherFunction(int& var) {
    std::cout << "myVar in otherFunction: "<< var<< std::endl;
    var = 20;
}

int main() {
    int myVar = 10;
    std::cout << "myVar in main: " << myVar<< std::endl;
    otherFunction(myVar);
    std::cout << "myVar in main after otherFunction: " << myVar<< std::endl;
    return 0;
}