Main.cc: In function ‘int main()’: Main.cc:10:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0;i < input.size();i++){ ~~^~~~~~~~~~~~~~ Main.cc:11:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i + 1 >= input.size() || input[i+1] != '-'){ ~~~~~~^~~~~~~~~~~~~~~ Main.cc:16:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i + 2 < input.size() && (int)(input[i]) <= (int)(input[i+2]) && ((input[i] >= '0' && input[i] <= '9' && input[i+2] >= 'a' && input[i+2] <= 'z') || (input[i+2] >= '0' && input[i+2] <= '9' && input[i] >= 'a' && input[i] <= 'z'))){ ~~~~~~^~~~~~~~~~~~~~ Main.cc:29:27: error: expected primary-expression before ‘)’ token for (int k = 0;k < ) ^ Main.cc:29:27: error: expected ‘;’ before ‘)’ token Main.cc:30:7: error: expected primary-expression before ‘}’ token } ^