实现复制的简单C ++程序中的输出错误

Question

    #include<iostream>
#include<vector>
using namespace std;
class test{
    int a,b;
    public:
    test():a{0},b{0}{}
    test(int,int);
    void copy(test);
    void print();
};
test::test(int a,int b){
    a=a;
    b=b;
}
void test::copy(test obj)
{
    a=obj.a;
    b=obj.b;
}
void test::print()
{
    cout<<test::a<<" <========> "<<b<<endl;
}
int main()
{
    test t1(4,15);
    t1.print();
    test t2=t1;
    t2.print();
}

The above code should print 4 <========> 15 4 <========> 15

but it is printing 1733802096 <========> 22093 1733802096 <========> 22093

I am not getting the problem. if I change the parameter name in the constructor it is giving correct output. What could be the reason for such behavior??

Answer 1

You are reassigning your parameters here:

test::test(int a,int b){
    a=a;  // You just set parameter a to its own value!
    b=b;
}

is not the same as:

test::test(int a,int b){
    this->a=a;
    this->b=b;
}

and should be replaced with:

test::test(int a,int b) : a(a), b(b) {}

all together.