/in/foo.c: In function 'main':
/in/foo.c:6:2: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
  scanf("%d %d",&n1,&n2);
  ^~~~~
/in/foo.c:6:2: warning: incompatible implicit declaration of built-in function 'scanf'
/in/foo.c:6:2: note: include '<stdio.h>' or provide a declaration of 'scanf'
/in/foo.c:12:2: warning: implicit declaration of function 'FindMaxs' [-Wimplicit-function-declaration]
  FindMaxs(a,n1);
  ^~~~~~~~
/in/foo.c: At top level:
/in/foo.c:19:6: warning: conflicting types for 'FindMaxs'
 void FindMaxs(int a[],int n)
      ^~~~~~~~
/in/foo.c:12:2: note: previous implicit declaration of 'FindMaxs' was here
  FindMaxs(a,n1);
  ^~~~~~~~
/in/foo.c: In function 'FindMaxs':
/in/foo.c:23:3: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
   printf("%d ",a[0]);
   ^~~~~~
/in/foo.c:23:3: warning: incompatible implicit declaration of built-in function 'printf'
/in/foo.c:23:3: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:27:7: warning: incompatible implicit declaration of built-in function 'printf'
       printf("%d ",a[i]);
       ^~~~~~
/in/foo.c:27:7: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:29:2: warning: incompatible implicit declaration of built-in function 'printf'
  printf("%d ",a[n-1]);
  ^~~~~~
/in/foo.c:29:2: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:21:8: warning: unused variable 'k' [-Wunused-variable]
  int i,k;
        ^