Examples from class

random-int-example.cpp

#include <iostream>
#include <string>
#include <cstdlib> // for rand(), srand(), time()
using namespace std;

const int NUMBER = 10;

// Example of a generalized function to return a random int in a range
int RandIntInRange(int min, int max) {
    // See zyBooks 5.15 for more info
    return rand() % (max - min + 1) + min;
}

int main() {
    // without srand() the sequence of random numbers would the the same
    // each time you run the program.
    // "Seeding" the random number with the time will fix this problem.
    // Most code with rand() will use srand(time(0)) in this way
    srand(time(0));

    for (int i = 0; i < NUMBER; ++i) {
        int number = RandIntInRange(2, 5);
        cout << number << endl;
    }

    return 0;
}

simple-vector-example.cpp

// This example isn't critical to understand at the moment,
// It was more to give a conceptual overview of what things
// we can create with code once we have the concept of list
// data (vectors and arrays).

// Once you complete the readings in chapter 6 this will
// make more sense, but feel free to take a look now! :)

#include <iostream>
#include <string>
#include <vector>

using namespace std;

int main() {
    // Create a vector (list) containing strings that we refer to by the name of "names".
    // It starts empty.
    vector<string> names;

    while (true) {
        string input;
        cout << "Enter your name: ";
        cin >> input;

        if (input == "DONE") {
            break;
        }

        // Add the input name to the end of the list.
        names.push_back(input);
    }

    // Output each name in the list on a new line
    // Notice that .size() and .at() are very similar to 
    // accessing chararcters in a string!
    for (int i = 0; i < names.size(); ++i) {
        // Access the string at index i in the list
        cout << names.at(i) << endl;
    }

    return 0;
}

string-find-example.cpp

#include <iostream>
#include <string>
using namespace std;

const int NOT_FOUND = -1;

int Find(string text, string search) {
    // Iterate through characters of the string (starting points)
    for (int i = 0; i < text.size(); i++) {
        // Assume that it does match until proven otherwise
        bool match = true;
        // Iterate through characters of the search string
        // Also check that we don't search beyond the `text` string's length
        // with (i + j) < text.size()
        for (int j = 0; j < search.size() && (i + j) < text.size(); j++) {
            // Compare each letter in the search string (j) with the letters in the
            // string to be searched (i). i + j is to ensure we are also stepping through
            // the characters in the string to be searched at the same rate as the search
            // string.
            if (text.at(i + j) != search.at(j)) {
                // If characters don't match we can set this to false
                match = false;
                break; // We can exit the loop early because we know for a fact it doesn't match
            }
        }
        // A match was found. Return the index of the first matching character.
        if (match) {
            return i;
        }
    }
    // We return a negative number to indicate that it wasn't found.
    // Because a valid position cannot be negative, -1 is a good option
    // to represent "not found".
    return NOT_FOUND; // similar to string::npos
}

int main() {
    string sentence;
    string search;

    cout << "Enter a sentence: ";
    getline(cin, sentence);

    cout << "Enter a search word: ";
    cin >> search;

    // Here it would be best to use sentence.find(search), but to
    // show an example of nested loops (and some principles of find
    // functions) this is a useful demo.
    int findIndex = Find(sentence, search);
    if (findIndex != NOT_FOUND) {
        cout << search << " was found at index " << findIndex << endl;
    }
    else {
        cout << search << " was not found in " << sentence << endl;
    }

    return 0;
}