C++ - Size of a struct

Question

Why is output 12?

#include <iostream>
using namespace std;

struct student{
char a; int c; char b;
};

int main() {
cout << sizeof(student);
return 0;
}

Answer 1

A good explanation is here:
https://www.geeksforgeeks.org/is-sizeof-for-a-struct-equal-to-the-sum-of-sizeof-of-each-member/amp/

Answer 2

Very clear, thank you!

Answer 3

Because char is considered to be 4 bytes in a struct.
it is 1 byte but 3 bytes are added to satisfy alignment constraints.