Function Call by Reference

#include <stdio.h>

void func1(int *a){
  printf("\nIn func1 the value of a is: %d",*a);
}

void func2(int *a){
  printf("\nIn func2 the value of a is: %d",*a);
}

int main()
{
  int a=10, *p;
  p=&a;
  
  printf("In Func Main");
  func1(p);
  func2(p);
  func1(p);
  return 0;
}

Output is

In Func Main
In func1 the value of a is: 10
In func2 the value of a is: 10
In func1 the value of a is: 10[?2004h