C++ Notes: Examples: Compress words

Problem

Read a sequence of words, eliminate all vowels ("aeiou", lower case only). If the resulting word has two or fewer characters, don't eliminate any vowels. Sort and print the words.

The modification of each word should be made by calling a void function, compressWord, where the word is the single parameter. This function must be defined in a separate file.

Example

Input
    This is the test data for a 
    first run.
Output
    Ths
    a
    dt
    fr
    frst
    is
    rn.
    th
    tst

Suggestions

A solution

There are many possible ways to solve this problem. Here is one.

The header file - compress.h

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// readModSortWrite/compress.h
// Fred Swartz - 2004-11-20

void compress(string& w);

The main program - readModSortWrite.cpp

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// stl-vector-mod-sort/readModSortWrite.cpp -- Read, compress, sort words.
// Fred Swartz - 2004-11-07

// This program is intended as an exercise in using 
//     vector, string, multiple source files, sort.
// It reads words, removes vowels (see rules in compress.cpp),
//     sorts, and prints them.

#include <iostream>
#include <stdlib.h>
#include <vector>
#include <algorithm>
using namespace std;

#include "compress.h"

//========================================================== main
int main() {
    string word;           // Used to save input word.
    vector<string> words;  // Save words here.
    
    //... Read, compress, and save words until EOF
    while (cin >> word) {
        compress(word);
        words.push_back(word);
    }
    
    //... Use STL sort to put them in alphabetical order.
    sort(words.begin(), words.end());
    
    //... Print the compressed, sorted words.
    for (int i=0; i<words.size(); i++) {
        cout << words[i] << endl;
    }
    
    system("PAUSE");  // Keep Dev-C++ window open	
    return 0;
}

The compress function - compress.cpp

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// readModSortWrite/compress.cpp - Read words, compress, sort, print.
// Fred Swartz - 2004-11-20

//  The compress() function removes vowels from its parameter.
//  1. If result would be shorter than two chars, it is unchanged.
//  2. Only lowercase characters are removed.

#include <string>
using namespace std;

#include "compress.h"

const char VOWELS[] = "aeiou";
const int VMAX = 5;

//========================================================= compress
void compress(string& w) {
    string temp = w;    // Save the original parameter.
    
    //... Don't change words that are already short.
    if (w.size() <= 2) {
        return;  // No need to even look if it's this short.
    }    
    
    //... Iterate character-by-character over each string.
    for (int i=w.size()-1; i >= 0; i--) {
        //... Iterate over each of the vowel characters.
        for (int v=0; v<VMAX; v++) {
            if (w[i] == VOWELS[v]) {  // When it's a vowel
                w.erase(i, 1);        // Remove it.
                break;                // Try next word character.
            }
        }
    } 
    
    //... If the result has fewer than two characters, use original.
    if (w.size() < 2) {
        w = temp;
    } 
}
Copyleft 2004 Fred Swartz MIT License