ref parm

/*
-Wall -Wextra -Wpedantic -Wshadow
*/

#include <stdio.h>

void Fnc1 ( int a )
{
    a++;
}

void Fnc2 ( int *a )
{
    (*a)++;
}

void Fnc3 ( int &a )
{
    a++;
}


int main()
{

    int a;


    a = 1;

    printf("(1) before: %d\n", a);

    Fnc1( a );

    printf("(1) after: %d\n", a);

/**********/

    a = 1;

    printf("(2) before: %d\n", a);

    Fnc2( &a );

    printf("(2) after: %d\n", a);

/**********/

    a = 1;

    printf("(3) before: %d\n", a);

    Fnc3( a );

    printf("(3) after: %d\n", a);


    return 0;
}

/*
output:

(1) before: 1
(1) after: 1
(2) before: 1
(2) after: 2
(3) before: 1
(3) after: 2

*/