pset 1

hello

Simple C program to print hello

hello.c

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

int main(void)
{
    string name = get_string("What's your name?\n");
    printf("hello, %s\n", name);
}

mario

Pyramid building

If the user doesn’t, in fact, input a positive integer between 1 and 8, inclusive, when prompted, the program should re-prompt the user until they cooperate:

$ ./mario
Height: -1
Height: 0
Height: 42
Height: 50
Height: 4
   #  #
  ##  ##
 ###  ###
####  ####

mario.c

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

void pyramid(int height);

int main(void)
{
    int height;

    do
    {
        height = get_int("Height: ");
    }
    while (height < 1 || height > 8);

    pyramid(height);
}

void pyramid(int height)
{
    int space = height - 1;
    int hash = 1;
    for (int i = 0; i < height; i++)
    {
        for (int j = 0; j < space; j++)
        {
            printf(" ");
        }
        for (int j = 0; j < hash; j++)
        {
            printf("#");
        }
        printf("  ");
        for (int j = 0; j < hash; j++)
        {
            printf("#");
        }
        space--;
        hash++;
        printf("\n");
    }
}

credit

Validation of AMEX, MASTERCARD, and VISA credit/debit cards using Luhn’s Algorithm

credit.c

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

#define dig12 1000000000000
#define dig13 10000000000000
#define dig14 100000000000000
#define dig15 1000000000000000

int dig = 0;

string serviceDetect(long long num);

bool fraudCheck(long long number);

int main(void)
{
    long long num = get_long("Number: ");
    if (fraudCheck(num))
    {
        printf("%s\n", serviceDetect(num));
    }
    else
    {
        printf("INVALID\n");
    }
}

bool fraudCheck(long long number)
{
    int mulsum = 0, regsum = 0;
    int buffer = 0;
    while (number > 0)
    {
        if (buffer == 0)
        {
            regsum += (number % 10);
            number /= 10;
            buffer = 1;
        }
        else
        {
            int k = 2 * (number % 10);
            if (k >= 10)
            {
                mulsum += (k % 10);
                k /= 10;
                mulsum += k;
            }
            else
            {
                mulsum += k;
            }
            number /= 10;
            buffer = 0;
        }
        dig++;
    }

    if ((mulsum + regsum) % 10)
    {
        return false;
        printf("false\n");
    }

    return true;
}

string serviceDetect(long long num)
{
    if (dig == 13 && (num / dig12) == 4)
    {
        return "VISA";
    }
    else if (dig == 16)
    {
        if ((num / dig15) == 4)
        {
            return "VISA";
        }
        else if (((num / dig14) >= 51) && ((num / dig14) <= 55))
        {
            return "MASTERCARD";
        }
        else
        {
            return "INVALID";
        }
    }
    else if (dig == 15)
    {
        if (((num / dig13) == 34) || ((num / dig13) == 37))
        {
            return "AMEX";
        }
        else
        {
            return "INVALID";
        }
    }
    else
    {
        return "INVALID";
    }
}