exercises

/**
 * File Handling - Exercises
 * Compile: g++ -std=c++17 -Wall exercises.cpp -o exercises
 */

#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include <vector>
using namespace std;

// ============================================================
// Exercise 1: Line Counter ⭐
// ============================================================

// TODO: Count lines, words, and characters in a file

void exercise1() {
    // int lines, words, chars;
    // countFile("file.txt", lines, words, chars);
    // cout << "Lines: " << lines << ", Words: " << words << ", Chars: " << chars;
    cout << "(Implement file counter)" << endl;
}

// ============================================================
// Exercise 2: File Copy ⭐
// ============================================================

// TODO: Copy contents from source to destination file

void exercise2() {
    // bool success = copyFile("source.txt", "dest.txt");
    cout << "(Implement file copy)" << endl;
}

// ============================================================
// Exercise 3: Search in File ⭐⭐
// ============================================================

// TODO: Search for a string in file, return line numbers

void exercise3() {
    // vector<int> lines = searchInFile("file.txt", "pattern");
    // Pattern found on lines: 5, 12, 23
    cout << "(Implement file search)" << endl;
}

// ============================================================
// Exercise 4: CSV Parser ⭐⭐
// ============================================================

// TODO: Parse CSV file into vector of vectors

void exercise4() {
    // auto data = parseCSV("data.csv");
    // Returns 2D vector of strings
    cout << "(Implement CSV parser)" << endl;
}

// ============================================================
// Exercise 5: Log Rotator ⭐⭐
// ============================================================

// TODO: If log file > maxSize, rename to .old and create new

void exercise5() {
    // rotateLog("app.log", 1024);  // Max 1KB
    cout << "(Implement log rotation)" << endl;
}

// ============================================================
// Exercise 6: Binary Record Manager ⭐⭐⭐
// ============================================================

// TODO: Create class to manage binary records
// - add(record)
// - get(id) -> record
// - update(id, record)
// - remove(id)

void exercise6() {
    // RecordManager rm("records.bin");
    // rm.add({1, "Alice", 95.5});
    // auto r = rm.get(1);
    cout << "(Implement binary record manager)" << endl;
}

// ============================================================
// Exercise 7: File Diff ⭐⭐⭐
// ============================================================

// TODO: Compare two files, output different lines

void exercise7() {
    // vector<pair<int, string>> diffs = fileDiff("file1.txt", "file2.txt");
    // Line 5 differs: "old text" vs "new text"
    cout << "(Implement file diff)" << endl;
}

// ============================================================
// Exercise 8: Config File Parser ⭐⭐⭐
// ============================================================

// TODO: Parse key=value config file into map
// Support comments (#) and sections [section]

void exercise8() {
    // auto config = parseConfig("app.conf");
    // config["database.host"] = "localhost"
    cout << "(Implement config parser)" << endl;
}

// ============================================================
// MAIN
// ============================================================

int main() {
    cout << "=== File Handling Exercises ===" << endl;
    
    cout << "\nEx1: Line Counter" << endl;
    exercise1();
    
    cout << "\nEx2: File Copy" << endl;
    exercise2();
    
    cout << "\nEx3: Search in File" << endl;
    exercise3();
    
    cout << "\nEx4: CSV Parser" << endl;
    exercise4();
    
    cout << "\nEx5: Log Rotator" << endl;
    exercise5();
    
    cout << "\nEx6: Binary Records" << endl;
    exercise6();
    
    cout << "\nEx7: File Diff" << endl;
    exercise7();
    
    cout << "\nEx8: Config Parser" << endl;
    exercise8();
    
    return 0;
}

// ============================================================
// ANSWERS
// ============================================================
/*
Ex1:
void countFile(const string& filename, int& lines, int& words, int& chars) {
    ifstream file(filename);
    lines = words = chars = 0;
    string line;
    while (getline(file, line)) {
        lines++;
        chars += line.length();
        stringstream ss(line);
        string word;
        while (ss >> word) words++;
    }
}

Ex2:
bool copyFile(const string& src, const string& dest) {
    ifstream in(src, ios::binary);
    ofstream out(dest, ios::binary);
    if (!in || !out) return false;
    out << in.rdbuf();
    return true;
}

Ex3:
vector<int> searchInFile(const string& filename, const string& pattern) {
    vector<int> results;
    ifstream file(filename);
    string line;
    int lineNum = 0;
    while (getline(file, line)) {
        lineNum++;
        if (line.find(pattern) != string::npos) {
            results.push_back(lineNum);
        }
    }
    return results;
}

Ex4:
vector<vector<string>> parseCSV(const string& filename) {
    vector<vector<string>> data;
    ifstream file(filename);
    string line;
    while (getline(file, line)) {
        vector<string> row;
        stringstream ss(line);
        string cell;
        while (getline(ss, cell, ',')) {
            row.push_back(cell);
        }
        data.push_back(row);
    }
    return data;
}

Ex8:
map<string, string> parseConfig(const string& filename) {
    map<string, string> config;
    ifstream file(filename);
    string line, section;
    while (getline(file, line)) {
        if (line.empty() || line[0] == '#') continue;
        if (line[0] == '[') {
            section = line.substr(1, line.find(']') - 1) + ".";
        } else {
            auto pos = line.find('=');
            if (pos != string::npos) {
                string key = section + line.substr(0, pos);
                string value = line.substr(pos + 1);
                config[key] = value;
            }
        }
    }
    return config;
}
*/