c++catchup week 3

bugged.cpp

#include <iostream>
#include <cstdlib>

int main() {
    int* i;
    std::cout << *i << '\n';
    return EXIT_SUCCESS;
}

numreader.cpp

#include <iostream>
#include <fstream>
#include <vector>
const int NUMARGS = 2;
const int FILEARG = 1;
std::vector<int> input() {
    int num;
    std::vector<int> nums;
    std::cout << "Please enter integers one at a time. Press ctrl-d to finish "
                 "entering numbers.\n";
    /* while std::cin.good() == true */
    while (std::cin >> num) {
        nums.push_back(num);
    }
    return nums;
}

bool writenums(const std::string& name, const std::vector<int>& nums) {
    std::ofstream out(name);
    if (!out.good()) {
        // failed to open file: permission denied
        perror("failed to open file");
        return false;
    }
    // || logical or
    out.exceptions(std::ifstream::failbit | std::ifstream::badbit);
    try {
        for (int i = 0; std::size_t(i) < nums.size(); ++i) {
            if (i > 0) {
                out << ',';
            }
            out << nums[i];
        }
    }
    catch (std::ios::failure& f) {
        perror("failure to write to file");
        out.close();
        return false;
    }
    out.close();
    return true;
}

int main(int argc, char** argv) {
    if (argc != NUMARGS) {
        std::cerr
            << "Error: invalid number of args. I need a filename to write to\n";
        return EXIT_FAILURE;
    }
    std::vector<int> theints = input();
    if (!writenums(argv[FILEARG], theints)) {
        std::cerr << "there was an error writing to the file\n";
    }
    return EXIT_SUCCESS;
}

numwriter.cpp

#include <iostream>
#include <fstream>
#include <vector>
const int NUMARGS = 2;
const int FILEARG = 1;
std::vector<int> input() {
    int num;
    std::vector<int> nums;
    std::cout << "Please enter integers one at a time. Press ctrl-d to finish "
                 "entering numbers.\n";
    /* while std::cin.good() == true */
    while (std::cin >> num) {
        nums.push_back(num);
    }
    return nums;
}

bool writenums(const std::string& name, const std::vector<int>& nums) {
    std::ofstream out(name);
    if (!out.good()) {
        // failed to open file: permission denied
        perror("failed to open file");
        return false;
    }
    // || logical or
    out.exceptions(std::ifstream::failbit | std::ifstream::badbit);
    try {
        for (int i = 0; std::size_t(i) < nums.size(); ++i) {
            if (i > 0) {
                out << ',';
            }
            out << nums[i];
        }
    }
    catch (std::ios::failure& f) {
        perror("failure to write to file");
        out.close();
        return false;
    }
    out.close();
    return true;
}

int main(int argc, char** argv) {
    if (argc != NUMARGS) {
        std::cerr
            << "Error: invalid number of args. I need a filename to write to\n";
        return EXIT_FAILURE;
    }
    std::vector<int> theints = input();
    if (!writenums(argv[FILEARG], theints)) {
        std::cerr << "there was an error writing to the file\n";
    }
    return EXIT_SUCCESS;
}