/in/foo.c: In function 'main':
/in/foo.c:4:9: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
    4 |         scanf("%d%d",&a,&b);
      |         ^~~~~
/in/foo.c:1:1: note: include '<stdio.h>' or provide a declaration of 'scanf'
  +++ |+#include <stdio.h>
    1 | int main()
/in/foo.c:4:9: warning: incompatible implicit declaration of built-in function 'scanf' [-Wbuiltin-declaration-mismatch]
    4 |         scanf("%d%d",&a,&b);
      |         ^~~~~
/in/foo.c:4:9: note: include '<stdio.h>' or provide a declaration of 'scanf'
/in/foo.c:8:20: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
    8 |                    printf("%d",c);}
      |                    ^~~~~~
/in/foo.c:8:20: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:8:20: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
/in/foo.c:8:20: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:11:16: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
   11 |                printf("%d",c);
      |                ^~~~~~
/in/foo.c:11:16: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:15:20: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
   15 |                    printf("%d",c);
      |                    ^~~~~~
/in/foo.c:15:20: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:21:20: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
   21 |                    printf("%d",c);
      |                    ^~~~~~
/in/foo.c:21:20: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:25:16: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
   25 |                printf("%d",c);
      |                ^~~~~~
/in/foo.c:25:16: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:29:20: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
   29 |                    printf("%d",c);
      |                    ^~~~~~
/in/foo.c:29:20: note: include '<stdio.h>' or provide a declaration of 'printf'