similarity and difference between "struct" and "class"

similarity:

1. struct is class, can declare, define field funcion

#include <stdio.h>

struct Person_s {
    int age;
    Person_s();
    Person_s(int age);
    void SetAge(int age);
    int GetAge();
};
Person_s::Person_s()
{
    this->age = 0;
}
Person_s::Person_s(int age)
{
    this->age = age;
}
void Person_s::SetAge(int age)
{
    this->age = age;
}
int Person_s::GetAge()
{
    return this->age;
}

class Person_c {
    int age;
    public:
    Person_c();
    Person_c(int age);
    void SetAge(int age);
    int GetAge();
};
Person_c::Person_c()
{
    this->age = 1;
}
Person_c::Person_c(int age)
{
    this->age = age;
}
void Person_c::SetAge(int age)
{
    this->age = age;
}
int Person_c::GetAge()
{
    return this->age;
}

void test()
{
    Person_s person1;
    Person_c person2;
    printf("person1.age: %d\n", person1.age);
    person1.age = 10;
    printf("person1.age: %d\n", person1.age);
    //printf("person2.age: %d\n", person2.age);
    //person1.age = 20;
    //printf("person2.age: %d\n", person2.age);
    printf("person2.age: %d\n", person2.GetAge());
    person2.SetAge(20);
    printf("person2.age: %d\n", person2.GetAge());

}
int main(int argc, char **argv)
{
    test();
}

 

difference:

1. class default field is private, struct default field is public