/in/foo.c: In function 'main':
/in/foo.c:6:5: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
     scanf("%d",&n);
     ^
/in/foo.c:6:5: warning: incompatible implicit declaration of built-in function 'scanf' [enabled by default]
/in/foo.c:19:5: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
     printf("%d",s);
     ^
/in/foo.c:19:5: warning: incompatible implicit declaration of built-in function 'printf' [enabled by default]