return不仅跳出了作用域，是可以直接结束函数的

#include <iostream>
#include <cstdlib>

int main()
{
    int a = 1;

    {
        if(a == 1){
            std::cout << "Hello, 1" << std::endl;
            return true;
        }
        std::cout << "Hello, 2" << std::endl;
    }
    std::cout << "Hello, 3" << std::endl;
}