Question

I am wondering if it is possible to cut down how many size_t variables I use here. Here is what I have:

std::size_t found, found2, found3, found4 /* etc */;

Each has its own string to find:

found1 = msg.find("string1");
found2 = msg.find("string2");
found3 = msg.find("string3");
found4 = msg.find("string4");
// etc

If the word is found, then it will discard and prevent the message to be shown:

if (found1 != std::string::npos)
{
    SendMsg("You cannot say that word!");
}

I have else if statements until found21. I’d like to cut everything down in size, so it would be clean, but I don’t have a clue how to do it. I would also like it to lowercase the word. I have never used tolower at all either, so I would appreciated it if someone would help me.

Answer 1

To lowercase a string, you can do

std::transform(msg.begin(), msg.end(), msg.begin(), std::tolower);

Transform takes a begin and end iterator as the first and second arguments, and for each element in that range, applies the fourth argument (a function) and assigns it to what the third iterator is pointing to and increments it. By passing msg.begin() as both the first and third arguments, it will assign the result of the function to what it passed to it. So transform will basically do this:

for (auto src = begin(msg), dst = begin(msg); src != end(msg); ++src, ++dst)
    *dst = tolower(*src);

but using transform is so much nicer.

To check whether a string contains any of a list of substrings, you can use a for loop with a vector:

vector<string> bad_strings { "bad word 1", "bad word 2", "etc" };

for (auto i = begin(bad_strings); i != end(bad_strings); ++i)
    if (msg.find(*i)) {
        SendMsg("You cannot say that word!");
        break; // stop when you find it matches even one bad string
    }