Converting a cstring to camelcase

Question

So my task is to fill out my function to work with a test driver that feeds it a random string during every run. For this function I have to convert the first character of every word to a capital and everything else must be lower.

It mostly works but the issue i'm having with my code is that it won't capitalize the very first character and if there is a period before the word like:

.word

The 'w' in this case would remain lower.

Here is my source:

void camelCase(char line[])
{
    int index = 0;
    bool lineStart = true;

    for (index;line[index]!='\0';index++)
    {
        if (lineStart)
        {
            line[index] = toupper(line[index]);
            lineStart = false;
        }

        if (line[index] == ' ')
        {
            if (ispunct(line[index]))
            {
                index++;
                line[index] = toupper(line[index]);
            }
            else
            {
                index++;
                line[index] = toupper(line[index]);
            }
        }else
            line[index] = tolower(line[index]);
    }
    lineStart = false;

}

I would say this logic is over-complicated given the task... — Eugene Sh., Apr 05 '16 at 19:22
Use more boolean flags. Don't just skip to the next index or you'll write past the end of the string. — Kijewski, Apr 05 '16 at 19:23

tonisuter · Accepted Answer · 2016-04-05T20:14:30.747

Here's a solution that should work and is a bit less complicated in my opinion:

#include <iostream>
#include <cctype>

void camelCase(char line[])  {
    bool active = true;

    for(int i = 0; line[i] != '\0'; i++) {
        if(std::isalpha(line[i])) {
            if(active) {
                line[i] = std::toupper(line[i]);
                active = false;
            } else {
                line[i] = std::tolower(line[i]);
            }
        } else if(line[i] == ' ') {
            active = true;
        }
    }
}

int main() {
    char arr[] = "hELLO, wORLD!";       // Hello, World!
    camelCase(arr);
    std::cout << arr << '\n';
}

The variable active tracks whether the next letter should be transformed to an uppercase letter. As soon as we have transformed a letter to uppercase form, active becomes false and the program starts to transform letters into lowercase form. If there's a space, active is set to true and the whole process starts again.

That's exactly it. Thanks for the help! – RyeMan Apr 05 '16 at 20:17 — RyeMan, Apr 05 '16 at 20:17

score 0 · Answer 2 · answered Nov 11 '22 at 10:26

Solution using std::string

void toCamelCase(std::string & s)
{
    char previous = ' ';
    auto f = [&](char current){
        char result = (std::isblank(previous) && std::isalpha(current)) ? std::toupper(current) : std::tolower(current);
        previous = current;
        return result;
    };
    std::transform(s.begin(),s.end(),s.begin(),f);
}

Converting a cstring to camelcase

2 Answers2