#include<stdio.h>

int foo();

int main()
{
  int c;
  printf("to stop press Control-D:");
  while( (c = getchar()) !=EOF){
    printf("foo invoked %d times\t",foo());
    printf("to stop press Control-D:");
  }
  return 0;
}


int foo()
{
  static int foo_invoke=0;
  foo_invoke ++;
  return foo_invoke;
}