/in/foo.c: In function 'main':
/in/foo.c:23:14: warning: comparison between pointer and integer [enabled by default]
  for(i=0;a[i]!=NULL;i++)
              ^
/in/foo.c:20:12: warning: unused variable 'k' [-Wunused-variable]
  int i=0,j,k,m;
            ^
/in/foo.c:20:10: warning: unused variable 'j' [-Wunused-variable]
  int i=0,j,k,m;
          ^
/in/foo.c: In function 'pd':
/in/foo.c:16:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
/in/foo.c: In function 'main':
/in/foo.c:27:8: warning: 'm' is used uninitialized in this function [-Wuninitialized]
  printf("a[i]=%d",m);
        ^
/in/foo.c: In function 'pd':
/in/foo.c:15:8: warning: 'm' may be used uninitialized in this function [-Wmaybe-uninitialized]
  printf("a[i]=%d",m);
        ^
/in/foo.c:8:4: warning: 'k' may be used uninitialized in this function [-Wmaybe-uninitialized]
   k++;
    ^