/in/foo.c: In function 'sushu':
/in/foo.c:4:2: error: expected declaration specifiers before 'for'
  for(int i=2;i<=sqrt(a);i++)
  ^~~
/in/foo.c:4:14: error: expected declaration specifiers before 'i'
  for(int i=2;i<=sqrt(a);i++)
              ^
/in/foo.c:4:25: error: expected declaration specifiers before 'i'
  for(int i=2;i<=sqrt(a);i++)
                         ^
/in/foo.c:13:1: error: expected '=', ',', ';', 'asm' or '__attribute__' before '{' token
 {
 ^
/in/foo.c:22:1: error: expected '{' at end of input
 }
 ^
/in/foo.c:22:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^