Week 2 Practice Problems

Hours:

#include <cs50.h>
#include <ctype.h>
#include <stdio.h>

float calc_hours(int hours[], int weeks, char output);

int main(void)
{
    int weeks = get_int("Number of weeks taking CS50: ");
    int hours[weeks];

    for (int i = 0; i < weeks; i++)
    {
        hours[i] = get_int("Week %i HW Hours: ", i);
    }

    char output;
    do
    {
        output = toupper(get_char("Enter T for total hours, A for average hours per week: "));
    }
    while (output != 'T' && output != 'A');

    printf("%.1f hours\n", calc_hours(hours, weeks, output));
}

// TODO: complete the calc_hours function
float calc_hours(int hours[], int weeks, char output)
{
    float num = 0;
    if (output == 'T')
    {
        for (int i = 0; i < weeks; i++)
        {
            num += hours[i];
        }
    }

    if (output == 'A')
    {
        for (int j = 0; j < weeks; j++)
        {
            num += hours[j];
        }
        num = num / weeks;
    }
    return num;
}

N0 V0w3ls:

// Write a function to replace vowels with numbers
// Get practice with strings
// Get practice with command line
// Get practice with switch

#include <cs50.h>
#include <stdio.h>
#include <string.h>

char replace(char c);

int main(int argc, string argv[])
{
    if (argc != 2)
    {
        printf("Usage: ./no-vowels word\n");
        return 1;
    }

    int i = 0;
    do
    {
        printf("%c", replace(argv[1][i]));
        i++;
    }
    while (i < strlen(argv[1]));
    printf("\n");
    return 0;
}

char replace(char c)
{
    switch (c)
    {
        case 'a':
            return '6';
            break;
        case 'e':
            return '3';
            break;
        case 'i':
            return '1';
            break;
        case 'o':
            return '0';
            break;
        default:
            return c;
            break;
    }
}

Password:

// Check that a password has at least one lowercase letter, uppercase letter, number and symbol
// Practice iterating through a string
// Practice using the ctype library

#include <cs50.h>
#include <ctype.h>
#include <stdio.h>
#include <string.h>

bool valid(string password);

int main(void)
{
    string password = get_string("Enter your password: ");
    if (valid(password))
    {
        printf("Your password is valid!\n");
    }
    else
    {
        printf("Your password needs at least one uppercase letter, lowercase letter, number and symbol\n");
    }
}

// TODO: Complete the Boolean function below
bool valid(string password)
{
    bool upper = false, lower = false, number = false, symbol = false;
    for (int i = 0, n = strlen(password); i < n; i++)
    {
        if (isupper(password[i]))
        {
            upper = true;
        }
        else if (islower(password[i]))
        {
            lower = true;
        }
        else if (isdigit(password[i]))
        {
            number = true;
        }
        else if (ispunct(password[i]))
        {
            symbol = true;
        }
    }
    if (upper == true && lower == true && number == true && symbol == true)
    {
        return true;
    }
    else
    {
        return false;
    }
}

Lab 2: Scrabble:

#include <cs50.h>
#include <ctype.h>
#include <stdio.h>
#include <string.h>

// Points assigned to each letter of the alphabet
int POINTS[] = {1, 3, 3, 2, 1, 4, 2, 4, 1, 8, 5, 1, 3, 1, 1, 3, 10, 1, 1, 1, 1, 4, 4, 8, 4, 10};

int compute_score(string word);

int main(void)
{
    // Get input words from both players
    string word1 = get_string("Player 1: ");
    string word2 = get_string("Player 2: ");

    // Score both words
    int score1 = compute_score(word1);
    int score2 = compute_score(word2);

    // TODO: Print the winner
    if (score1 > score2)
    {
        printf("Player 1 wins!");
    }
    else if (score1 < score2)
    {
        printf("Player 2 wins!");
    }
    else
    {
        printf("Tie!");
    }
}

int compute_score(string word)
{
    // TODO: Compute and return score for string
    int score = 0;
    for (int i = 0; i < strlen(word); i++)
    {
        if (islower(word[i]))
        {
            score += POINTS[word[i] - 97];
        }
        else if (isupper(word[i]))
        {
            score += POINTS[word[i] - 65];
        }
    }
    return score;
}

Problem Set 2

Readability:

#include <cs50.h>
#include <ctype.h>
#include <math.h>
#include <stdio.h>
#include <string.h>

int count_letters(string text);
int count_words(string text);
int count_sentences(string text);

int main(void)
{
    string text = get_string("Text: ");
    int letters = count_letters(text);
    int words = count_words(text);
    int sentences = count_sentences(text);
    float L = (float) letters / words * 100;
    float S = (float) sentences / words * 100;
    int index = round(0.0588 * L - 0.296 * S - 15.8);
    if (index < 1)
    {
        printf("Before Grade 1\n");
    }
    else if (index >= 1 && index < 16)
    {
        printf("Grade %i\n", index);
    }
    else if (index >= 16)
    {
        printf("Grade 16+\n");
    }
}

int count_letters(string text)
{
    int all = strlen(text);
    int letters = 0;
    for (int i = 0; i < all; i++)
    {
        if (isalpha(text[i]))
        {
            letters += 1;
        }
    }
    return letters;
}

int count_words(string text)
{
    int all = strlen(text), words = 1;
    for (int i = 0; i < all; i++)
    {
        if (isspace(text[i]))
        {
            words += 1;
        }
    }
    return words;
}

int count_sentences(string text)
{
    int all = strlen(text), sentences = 0;
    for (int i = 0; i < all; i++)
    {
        if (text[i] == '.' || text[i] == '!' || text[i] == '?')
        {
            sentences += 1;
        }
    }
    return sentences;
}

Wordle50, if feeling more comfortable:

#include <cs50.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

// each of our text files contains 1000 words
#define LISTSIZE 1000

// values for colors and score (EXACT == right letter, right place; CLOSE == right letter, wrong place; WRONG == wrong letter)
#define EXACT 2
#define CLOSE 1
#define WRONG 0

// ANSI color codes for boxed in letters
#define GREEN "\e[38;2;255;255;255;1m\e[48;2;106;170;100;1m"
#define YELLOW "\e[38;2;255;255;255;1m\e[48;2;201;180;88;1m"
#define RED "\e[38;2;255;255;255;1m\e[48;2;220;20;60;1m"
#define RESET "\e[0;39m"

// user-defined function prototypes
string get_guess(int wordsize);
int check_word(string guess, int wordsize, int status[], string choice);
void print_word(string guess, int wordsize, int status[]);

int main(int argc, string argv[])
{
    // ensure proper usage
    // TODO #1
    int wordsize = 0;

    if (argc != 2)
    {
        printf("Usage: ./wordle wordsize\n");
        return 1;
    }

    // ensure argv[1] is either 5, 6, 7, or 8 and store that value in wordsize instead
    // TODO #2
    else if (argv[1][0] == '5' || argv[1][0] == '6' || argv[1][0] == '7' || argv[1][0] == '8')
    {
        wordsize = (int) argv[1][0] - '0';
    }
    else
    {
        printf("Error: wordsize must be either 5, 6, 7, or 8\n");
        return 1;
    }

    // open correct file, each file has exactly LISTSIZE words
    char wl_filename[6];
    sprintf(wl_filename, "%i.txt", wordsize);
    FILE *wordlist = fopen(wl_filename, "r");
    if (wordlist == NULL)
    {
        printf("Error opening file %s.\n", wl_filename);
        return 1;
    }

    // load word file into an array of size LISTSIZE
    char options[LISTSIZE][wordsize + 1];

    for (int i = 0; i < LISTSIZE; i++)
    {
        fscanf(wordlist, "%s", options[i]);
    }

    // pseudorandomly select a word for this game
    srand(time(NULL));
    string choice = options[rand() % LISTSIZE];

    // allow one more guess than the length of the word
    int guesses = wordsize + 1;
    bool won = false;

    // print greeting, using ANSI color codes to demonstrate
    printf(GREEN "This is WORDLE50" RESET "\n");
    printf("You have %i tries to guess the %i-letter word I'm thinking of\n", guesses, wordsize);

    // main game loop, one iteration for each guess
    for (int i = 0; i < guesses; i++)
    {
        // obtain user's guess
        string guess = get_guess(wordsize);

        // array to hold guess status, initially set to zero
        int status[wordsize];

        // set all elements of status array initially to 0, aka WRONG
        // TODO #4
        for (int j = 0; j < wordsize; j++)
        {
            status[j] = WRONG;
        }

        // Calculate score for the guess
        int score = check_word(guess, wordsize, status, choice);

        printf("Guess %i: ", i + 1);

        // Print the guess
        print_word(guess, wordsize, status);

        // if they guessed it exactly right, set terminate loop
        if (score == EXACT * wordsize)
        {
            won = true;
            break;
        }
    }

    // Print the game's result
    // TODO #7
    if (won)
    {
        printf("You won!\n");
    }
    else
    {
        printf("%s\n", choice);
    }

    // that's all folks!
    return 0;
}

string get_guess(int wordsize)
{
    string guess = "";
    int number = 0;

    // ensure users actually provide a guess that is the correct length
    // TODO #3
    do
    {
        guess = get_string("Input a %i-letter word: ", wordsize);
    }
    while (strlen(guess) != wordsize);
    for (int i = 0; i < strlen(guess); i++)
    {
        if (isalnum(guess[i]) == 0)
        {
            get_guess(wordsize);
            break;
        }
        else if (isdigit(guess[i]))
        {
            get_guess(wordsize);
            break;
        }
        else if (isupper(guess[i]))
        {
            guess[i] = tolower(guess[i]);
        }
    }
    return guess;
}

int check_word(string guess, int wordsize, int status[], string choice)
{
    int score = 0;

    // compare guess to choice and score points as appropriate, storing points in status
    // TODO #5

    // HINTS
    // iterate over each letter of the guess
    // iterate over each letter of the choice
    // compare the current guess letter to the current choice letter
    // if they're the same position in the word, score EXACT points (green) and break so you don't compare that letter further
    // if it's in the word, but not the right spot, score CLOSE point (yellow)
    // keep track of the total score by adding each individual letter's score from above
    for (int i = 0; i < wordsize; i++)
    {
        char gu = guess[i];
        if (guess[i] == choice[i])
        {
            status[i] = EXACT;
        }
        else
        {
            for (int j = 0; j < wordsize; j++)
            {
                if (status[j] != EXACT)
                {
                    if (gu == choice[j])
                    {
                        status[i] = CLOSE;
                    }
                }
            }
        }
    }
    for (int m = 0; m < wordsize; m++)
    {
        score += status[m];
    }
    return score;
}

void print_word(string guess, int wordsize, int status[])
{
    // print word character-for-character with correct color coding, then reset terminal font to normal
    // TODO #6
    for (int i = 0; i < wordsize; i++)
    {
        if (status[i] == EXACT)
        {
            printf(GREEN "%c" RESET, guess[i]);
        }
        else if (status[i] == CLOSE)
        {
            printf(YELLOW "%c" RESET, guess[i]);
        }
        else
        {
            printf(RED "%c" RESET, guess[i]);
        }
    }

    printf("\n");
    return;
}