/in/foo.c: In function 'main':
/in/foo.c:5:9: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
         scanf("%lld",&a[i]);
         ^~~~~
/in/foo.c:5:9: warning: incompatible implicit declaration of built-in function 'scanf'
/in/foo.c:5:9: note: include '<stdio.h>' or provide a declaration of 'scanf'
/in/foo.c:7:5: warning: incompatible implicit declaration of built-in function 'scanf'
     scanf("%lld",&b);
     ^~~~~
/in/foo.c:7:5: note: include '<stdio.h>' or provide a declaration of 'scanf'
/in/foo.c:13:5: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
     printf("%lld",c);
     ^~~~~~
/in/foo.c:13:5: warning: incompatible implicit declaration of built-in function 'printf'
/in/foo.c:13:5: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:2:29: warning: unused variable 'n' [-Wunused-variable]
     long long a[11],b=0,c=0,n,i;
                             ^