I have a question about structs

Question

What is the output of this code?
struct A{
int a;
float b;
};
struct B{
int b;
float a;
};
struct C{
A a; B b;
};
int main()
{
C c1={1,2,3,4};
C c2={5,6,7,8};
cout<<c1.b.a+c2.a.b;
//Can you tell me this question with reasons?
}

Answer 1

#include<iostream>
using namespace std;

struct A {
int a;
float b;
};

struct B {
int b;
float a;
};

struct C {
A a;
B b;
};

int main ()
{
// c1 is an instance of C struct.
// Inside C struct 2 instances are created.
// One of type A called a and another of
// type B called b.
// Type(struct) A and B, each has two variables.
// One int and another float.
//
// As a result, you've got to initialize those ints and floats
// in order to use each instances .
// In fact, the corrected version is like this

C c1 = {1, 2.0f, 3, 4.0f}; // {c1.a.a, c1.a.b, c1.b.b, c1.b.a}

C c2 = {5, 6.0f, 7, 8.0f}; // {c2.a.a, c2.a.b, c2.b.b, c2.b.a}

cout << c1.b.a + c2.a.b; // 4.0f + 6.0f = 10.0f
//Can you tell me this question with reasons?
}

Answer 2

Wow, good answer👍, by the way inserting this "//Can you tell me this question with reasons" into your answer better than your answer. @Babak