Hashmaps in C++

phoneBook.cpp

/**
 * phoneBook.cpp:
 *   Hashmaps in C++ - Kolby Heacock
 *
 * build:
 *   clang++ -std=c++2a test.cpp -o phonebook
 *
 * run:
 *   ./phonebook < input
 *
 * reference:
 *   https://www.hackerrank.com/challenges/30-dictionaries-and-maps/problem
 */

#include <algorithm>
#include <climits>
#include <cmath>
#include <cstdio>
#include <iostream>
#include <unordered_map>
#include <sstream>
#include <string>
#include <cstring>
#include <vector>
using namespace std;

int main() {
    unordered_map<string, string> phoneBook;
    char line[USHRT_MAX];
    unsigned long lineNumber = 0;
    unsigned long entries = 0;
    unsigned long queries = 0;
    unsigned long wordNumber = 0;

    while (cin) {
        if (cin.getline(line, USHRT_MAX)) {
            ++lineNumber;
            if (lineNumber == 1) {
                // Read number of entries
                entries = stoi(line);
            } else if (lineNumber <= 1 + entries) {
                // Populate phone book
                char *word = strtok(line, " ");
                string key = "";
                string value = "";
                while (word != NULL) {
                    ++wordNumber;
                    if (wordNumber == 1) {
                        key = word;
                    } else if (wordNumber == 2) {
                        value = word;
                    }
                    word = strtok(NULL, " ");
                }
                wordNumber = 0;
                if(key != "" && value != "") {
                    phoneBook.insert({key, value});
                }
            } else {
                // Filter phoneBook by queries
                if (phoneBook.find(string(line)) != phoneBook.end()){
                    cout << line << "=" << phoneBook[line] << endl;
                } else {
                    cout << "Not found" << endl;
                }
            }
        }
    }

    // Display phone book

    /*
    for (auto i = phoneBook.begin(); i != phoneBook.end(); ++i) {
        cout << i->first << " = " << i->second << endl;
    }
    */

    return 0;
}