What are the differences between a class and a structure in C++?

In C++, technically, the difference between the struct and class is that the struct is public by default and the class is private. Generally, we use the struct to carry the data. See the below comparison chart for struct and class,

Let see two example codes to understand the difference between struct and class.

Example-1:

#include <iostream>
using namespace std;
class Test
{
    int x; // Default: x is private
};
int main()
{
    Test t;
    
    t.x = 20; // compiler error because x is private
    
    return 0;
}

Output: error: ‘int Test::x’ is private|

Example-2:

#include <iostream>
using namespace std;
struct Test
{
    int x; // Default: x is public
};
int main()
{
    Test t;
    t.x = 20; // No compiler error because x is public
    cout << t.x;
    return 0;
}

Output: 20