CS50 Problem Set 2#

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#include <cs50.h>
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#include <ctype.h>
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#include <stdio.h>
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#include <string.h>
5

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int compute_score(string word);
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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};
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int main(void)
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{
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    string word1 = get_string("Player 1: ");
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    string word2 = get_string("Player 2: ");
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    int score1 = compute_score(word1);
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    int score2 = compute_score(word2);
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    if (score1 > score2)
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    {
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        printf("Player 1 wins!\n");
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        return 0;
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    }
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    else if (score1 < score2)
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    {
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        printf("Player 2 wins!\n");
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        return 0;
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    }
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    else
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    {
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        printf("Tie!\n");
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        return 0;
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    }
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}
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int compute_score(string word)
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{
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    int score = 0;
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    for (int i = 0; i < strlen(word); i++)
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    {
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        if (isupper(word[i]))
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        {
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            score += points[word[i] - 'A'];
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        }
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        else if (islower(word[i]))
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        {
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            score += points[word[i] - 'a'];
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        }
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    }
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    return score;
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}

1
#include <cs50.h>
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#include <ctype.h>
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#include <math.h>
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#include <stdio.h>
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#include <string.h>
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int letters(string text);
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int sentences(string text);
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int words(string text);
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int main(void)
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{
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    string text = get_string("Text: ");
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    int index = (int) round(0.0588 * letters(text) / words(text) * 100 -
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                            0.296 * sentences(text) / words(text) * 100 - 15.8);
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    if (index < 1)
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    {
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        printf("Before Grade 1\n");
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        return 0;
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    }
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    else if (index >= 16)
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    {
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        printf("Grade 16+\n");
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        return 0;
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    }
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    else
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    {
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        printf("Grade %i\n", index);
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        return 0;
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    }
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}
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int words(string text)
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{
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    int words = 1;
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    for (int i = 0; i < strlen(text); i++)
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    {
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        if (text[i] == ' ')
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        {
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            words += 1;
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        }
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    }
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    return words;
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}
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int letters(string text)
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{
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    int letters = 0;
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    for (int i = 0; i < strlen(text); i++)
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    {
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        if (isalpha(text[i]))
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        {
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            letters += 1;
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        }
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    }
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    return letters;
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}
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int sentences(string text)
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{
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    int sentences = 0;
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    for (int i = 0; i < strlen(text); i++)
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    {
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        if (text[i] == '.' || text[i] == '!' || text[i] == '?')
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        {
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            sentences += 1;
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        }
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    }
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    return sentences;
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}

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#include <cs50.h>
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#include <ctype.h>
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#include <stdio.h>
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#include <string.h>
5

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int main(int argc, string argv[])
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{
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    string key = argv[1];
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    if (argc != 2)
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    {
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        printf("Usage: ./substitution key\n");
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        return 1;
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    }
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    else if (strlen(argv[1]) != 26)
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    {
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        printf("Key must contain 26 characters.\n");
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        return 1;
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    }
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    else
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    {
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        for (int i = 0, n = strlen(key); i < n; i++)
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        {
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            if (isalpha(argv[1][i]) == 0)
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            {
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                printf("Key should be all alphabets.\n");
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                return 1;
27
            }
28

29
            for (int j = i + 1; j < n; j++)
30
            {
31
                if (argv[1][i] == argv[1][j] || argv[1][i] + 32 == argv[1][j] ||
32
                    argv[1][i] - 32 == argv[1][j])
33
                {
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                    printf("There should be no duplicate in the key.\n");
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                    return 1;
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                }
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            }
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        }
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        string ptext = get_string("plaintext:  ");
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        printf("ciphertext: ");
41
        for (int i = 0, length = strlen(ptext); i < length; i++)
42
        {
43
            if (isupper(ptext[i]))
44
            {
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                char result = toupper(key[ptext[i] - 'A']);
46
                printf("%c", result);
47
            }
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            else if (islower(ptext[i]))
49
            {
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                char result = tolower(key[ptext[i] - 'a']);
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                printf("%c", result);
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            }
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            else
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            {
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                printf("%c", ptext[i]);
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            }
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        }
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        printf("\n");
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        return 0;
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    }
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}