CODEWITHSUNDEEP
c++stringsubstringstringstream
blulow
blulow

Reputation: 41

How to remove all the words from a string that start with a certain character in C++

I have to create a function in C++ that would remove all the words from a string that start with a certain character inputted by a user. For example, if I were to have a string "She made up her mind to meet up with him in the morning" and a substring "m", I would get a result string "She up her to up with him in the". I believe I would need to find the occurrences of "m", erase it and all the characters after it till the space " ". Would that be the right approach and if so what would be the best methods to use in this case?

Upvotes: 0

Views: 484

Answers (3)

Saint-Martin
Saint-Martin

Reputation: 316

Simple example in french. You are a classy gentleman and dont want to say "merde" too often. This is very hard, so you decided not to say any word starting with 'm'. This program will help you :

"merde je suis beau merde je le sais" becomes "je suis beau je le sais"

#include <string>
#include <algorithm>
#include <iostream>
int main () {
  std::string str ("merde je suis beau merde je le sais");
  const auto forbidden_start ('m');
  std::cout << "initial rude string (words starting with \'" << forbidden_start << "\" : \"" << str << "\"" << std::endl;
  auto i (str.begin ());
  auto wait ((int) 0);
  std::for_each (str.begin (), str.end (), [&i, &forbidden_start, &wait] (const auto& c) {
    if (wait) {
      if (c == ' ') --wait;
    }
    else {
      if (c == forbidden_start) ++wait;
      else *i++ = c;
    }
  });
  if (i != str.end ()) str.erase (i, str.end ());
  std::cout << "\tpolite string : \"" << str << "\"" << std::endl;
}

All is not tested (separator is " "), but it is the idea

Upvotes: 1

blulow
blulow

Reputation: 41

What I needed to read about was how stringstream and >> work. Thanks everyone for the help! Here is the code.

void deleteWordsStartingWithChar(string& str, char c) {
    istringstream ss(str);
    ostringstream oss;
    std::string word;    
    while (ss >> word) {
        if (word[0] == c) {
            continue;
        }
        oss << word << " ";
    }

    str = oss.str();
}

Upvotes: 0

selbie
selbie

Reputation: 104589

Here's a hint. I'm guessing this is a homework problem. And I'm probably giving too much away.


std::string GetNextWord(const std::string &s, size_t pos)
{
   std::string word;

   // your code goes here to return a string that includes all the chars starting from s[pos] until the start of the next word (including trailing whitespace)

   // return an empty string if at the end of the string
   return word;
}

std::string StripWordsThatBeginWithLetter(const std::string& s, char c)
{
    std::string result;
    std::string word;
    size_t pos = 0;

    while (true)
    {
        word = GetNextWord(s, pos);
        pos += word.size();
        if (word.size() == 0)
        {
            break;
        }
       
        // your code on processing "word" goes here with respect
        // to "c" goes here
    }

    return result;
}

Upvotes: 3

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