Main.cc: In function ‘int main()’:
Main.cc:12:18: error: expression list treated as compound expression in initializer [-fpermissive]
int digit(x,y);
^
Main.cc:12:18: warning: left operand of comma operator has no effect [-Wunused-value]
Main.cc:12:9: warning: unused variable ‘digit’ [-Wunused-variable]
int digit(x,y);
^~~~~