c++ string iterator

Question

I'm trying to do an if statement inside a loop with an iterator over a string, but can't figure out how to get the current character for the if statement:

for (std::string::iterator i=buffer.end()-1; i>=buffer.begin(); --i) {
    if (!isalpha(*i) && !isdigit(*i)) {
        if(i != "-") { // obviously this is wrong
            buffer.erase(i);
        }
    }
}

Can someone help me get the current character so I can do some additional if statements?

Answer 1

I can't figure out how to get the current character

You do it twice here:

if (!isalpha(*i) && !isdigit(*i))

When you dereference an iterator (*i), you get the element to which it points.

"-"

This is a string literal, not a character. Character constants use single quotes, e.g., '-'.

for (std::string::iterator i=buffer.end()-1; i>=buffer.begin(); --i)

This would be much simpler with reverse iterators:

for (std::string::reverse_iterator i = buffer.rbegin(); i != buffer.rend(); ++i)

Answer 2

if(i != "-")

should be

if(*i != '-')