Question

I wrote a function in c++ to remove parenthesis from a string, but it doesn’t always catch them all for some reason that I’m sure is really simple.

string sanitize(string word)
{
int i = 0;

while(i < word.size())
{
    if(word[i] == '(' || word[i] == ')')
    {
        word.erase(i,1);
    }
    i++;
}
return word;
}

Sample result:

Input: ((3)8)8)8)8))7

Output: (38888)7

Why is this? I can get around the problem by calling the function on the output (so running the string through twice), but that is clearly not “good” programming. Thanks!

Answer 1

if(word[i] == '(' || word[i] == ')')
{
    word.erase(i,1);
}
i++;

If you erase a parenthesis, the next character moves to the index previously occupied by the parenthesis, so it is not checked. Use an else.

if(word[i] == '(' || word[i] == ')')
{
    word.erase(i,1);
} else {
    i++;
}