#include <stdio.h>
int f(int x, int *py, int **ppz) {
**ppz += 1;
*py += 2;
x += 3;
return x + *py + **ppz;
}
int main() {
int c = 4;
int *b = &c;
int **a = &b;
printf("%d\n", f(c, b, a));
}
$c$ is passed by value
x is just a local variable of f, it is not same as c,( call by value) while calling the function f, c's value was passed to it, that's it. Any changes to c's ( using its pointer variable) value will not effect x 's value.
$**ppz += 1$ will modify the value of c to 5
$*py += 2$ will modify the value of c to 7
$x = x + 3 = 7$ (local to f )
$x + *py + **ppy = 7 + 7 + 7 = 21$
