cpp-coding-exercise/integer-factorization/main.cpp at main · DoctorLai/cpp-coding-exercise · GitHub

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/**

* This program implements various algorithms for integer factorization,

* It takes integer(s) from the command line or a file and outputs their prime

* factorizations.

* Usage:

* ./integer-factorization [options] [integers...]

* Options:

* -h, --help Show this help message and exit

* -f, --file FILE Read integers from FILE, one per line

* -o, --output FILE Write output to FILE instead of stdout

#include <iostream>

#include <fstream>

#include <vector>

#include <string>

#include <getopt.h>

#include "factorization_algorithms.hpp"

void

print_help()

{

std::cout << "Usage: ./integer-factorization [options] [integers...]\n"

<< "Options:\n"

<< " -h, --help Show this help message and exit\n"

<< " -f, --file FILE Read integers from FILE, one per line\n"

<< " -o, --output FILE Write output to FILE instead of stdout\n";

}

int

main(int argc, char* argv[])

{

std::string input_file;

std::string output_file;

std::vector<long long> numbers;

static struct option long_options[] = {

{"help", no_argument, 0, 'h'},

{"file", required_argument, 0, 'f'},

{"output", required_argument, 0, 'o'},

{0, 0, 0, 0}};

int opt;

while ((opt = getopt_long(argc, argv, "hf:o:", long_options, NULL)) != -1) {

switch (opt) {

case 'h':

print_help();

return 0;

case 'f':

input_file = optarg;

break;

case 'o':

output_file = optarg;

break;

default:

print_help();

return 1;

}

// Read numbers from file if specified

if (!input_file.empty()) {

std::ifstream infile(input_file);

long long num;

while (infile >> num) {

numbers.push_back(num);

}

// Read numbers from command line arguments

for (int index = optind; index < argc; index++) {

numbers.push_back(std::stoll(argv[index]));

}

// Prepare output stream

std::ostream* out_stream = &std::cout;

std::ofstream outfile;

if (!output_file.empty()) {

outfile.open(output_file);

out_stream = &outfile;

}

// Factor each number and output the result

for (const auto& number : numbers) {

std::vector<long long> factors;

factors = trial_division(number);

*out_stream << "Factors of " << number << ": ";

for (const auto& factor : factors) {

*out_stream << factor << " ";

}

*out_stream << "\n";

}

if (outfile.is_open()) {

outfile.close();

}

return 0;

}

cpp-coding-exercise/integer-factorization/main.cpp at main · DoctorLai/cpp-coding-exercise · GitHub

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