Answer to Question #350970 in C++ for BScInf

Question

Write a program to remove unnecessary blanks from a text file. Your program should read the text file and copy it to another text file, but whenever more than one blank occurs consecutively, only one blank should be copied to the second file. The second file should be identical to the first file, except that all consecutive blanks have been replaced by a single blank.

Answer 1

#include <iostream>
#include <fstream>
#include <string>
#include <cstring>

using namespace std;

string readfile(const char* filename);
void writeFile(string content, const char* filename);
string delBlanks(string input);

int main()
{
    string in, out;
    cout << "Enter input filename: ";
    cin >> in;
    string s = delBlanks(readfile(in.c_str()));
    cout << "Enter output filename: ";
    cin >> out;
    writeFile(s, out.c_str());
    return 0;
}


string readfile(const char* filename) {
    ifstream ifs;
    string line, content;
    ifs.open(filename, fstream::in);
    while (ifs.good()) {
        getline(ifs, line);
        content += line + "\n";
    }
    return content;
}

void writeFile(string content, const char* filename) {
    ofstream ofs;
    ofs.open(filename, fstream::out | fstream::trunc);
    ofs << content;
}

string delBlanks(string s) {
    string res;
    while (strlen(s.c_str()) != 0) {
        while (s.substr(0, 1) == " ") {
            s = s.substr(1, strlen(s.c_str()) - 1);
        }
        if (s.find(" ") != string::npos) {
            res += s.substr(0, s.find(" ") + 1);
            s = s.substr(s.find(" ") + 1, strlen(s.c_str()) - (s.find(" ") + 1));
        } else {
            res += s;
            s = "";
        }
    }
    return res;
}