/in/foo.c: In function 'random':
/in/foo.c:4:13: warning: implicit declaration of function 'rand' [-Wimplicit-function-declaration]
  return 1LL*rand()*rand()%50+1;
             ^~~~
/in/foo.c:5:5: warning: 'main' is normally a non-static function [-Wmain]
 int main()
     ^~~~
/in/foo.c: In function 'main':
/in/foo.c:7:5: error: 'cout' undeclared (first use in this function)
     cout<<30;
     ^~~~
/in/foo.c:7:5: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c: In function 'random':
/in/foo.c:12:1: error: expected declaration or statement at end of input
 }
 ^
At top level:
/in/foo.c:5:5: warning: 'main' defined but not used [-Wunused-function]
 int main()
     ^~~~