Passing by reference in C

Question

If C does not support passing a variable by reference, why does this work?

#include 

void f(int *j) {
  (*j)++;
}

int main() {
  int i = 20;         


        

Answer 1

What you are doing is pass by value not pass by reference. Because you are sending the value of a variable 'p' to the function 'f' (in main as f(p);)

The same program in C with pass by reference will look like,(!!!this program gives 2 errors as pass by reference is not supported in C)

#include 

void f(int &j) {    //j is reference variable to i same as int &j = i
  j++;
}

int main() {
  int i = 20;
  f(i);
  printf("i = %d\n", i);

  return 0;
}

Output:-

3:12: error: expected ';', ',' or ')' before '&' token
             void f(int &j);
                        ^
9:3:  warning: implicit declaration of function 'f'
               f(a);
               ^