/in/foo.c:2:1: warning: parameter names (without types) in function declaration
 int B(n,k,m);
 ^~~
/in/foo.c: In function 'B':
/in/foo.c:11:5: warning: type of 'n' defaults to 'int' [-Wimplicit-int]
 int B(n,k,m)
     ^
/in/foo.c:11:5: warning: type of 'k' defaults to 'int' [-Wimplicit-int]
/in/foo.c:11:5: warning: type of 'm' defaults to 'int' [-Wimplicit-int]
/in/foo.c:15:5: error: expected expression before ')' token
  if()
     ^