1

I've been trying to implement those two function whole day and something seems to not be working because the printf function I wrote in find.c outputs 9,8,7,6,5,6,7,8,9 when I input the numbers from 9 to 1 as straws. I think the problem comes when value > m but I can't find a solution, so I'm hoping any of you guys gives me a tip.

The code with the two functions:

/**
 * helpers.c
 *
 * Computer Science 50
 * Problem Set 3
 *
 * Helper functions for Problem Set 3.
 */

#include <cs50.h>

#include "helpers.h"

/**
 * Returns true if value is in array of n values, else false.
 */
bool search(int value, int values[], int n)
{
    int min = 0;
    int max = n - 1;
    // TODO: implement a searching algorithm
   while(min <= max)
   {
       int midpoint = (min + max) / 2;
       if (value == values[midpoint])
       {
           return true;
       }
       else if (value > values[midpoint])
       {
           min = midpoint + 1;
       }
       else if (value < values[midpoint])
       {
           max = midpoint - 1 ;
       }
   }
   return false;
}

/**
 * Sorts array of n values.
 */
void sort(int values[], int n)
{
    // TODO: implement an O(n^2) sorting algorithm
    for(int i = 0; i < n; i++)
    {
        int min = i;
        for(int j = i + 1; j < n; j++)
        {
            if(values[j] < values[min])
            {
                min = j;
            }
        }
        if(min != i)
        {
            values[min] = values[i];
        }
    }
}
1
  • By the way, the code goes through check50 without giving any errors. – Petar Petrov Aug 12 '16 at 23:14
1

I figured it out. It seems like I didn't manage to swap values[i] and values[min] in selection sort the right way, so I did a bit of researching and saw that I need a third integer to do that. Here is the fixed code:

/**
 * helpers.c
 *
 * Computer Science 50
 * Problem Set 3
 *
 * Helper functions for Problem Set 3.
 */

#include <cs50.h>

#include "helpers.h"

/**
 * Returns true if value is in array of n values, else false.
 */
bool search(int value, int values[], int n)
{
    int min = 0;
    int max = n - 1;
    // TODO: implement a searching algorithm
   while(min <= max)
   {
       int midpoint = (min + max) / 2;
       if (value == values[midpoint])
       {
           return true;
       }
       else if (value > values[midpoint])
       {
           min = midpoint + 1;
       }
       else if (value < values[midpoint])
       {
           max = midpoint - 1 ;
       }
   }
   return false;
}

/**
 * Sorts array of n values.
 */
void sort(int values[], int n)
{
    // TODO: implement an O(n^2) sorting algorithm
    for(int i = 0; i < n; i++)
    {
        int min = i;
        for(int j = i + 1; j < n; j++)
        {
            if(values[j] < values[min])
            {
                min = j;
            }
        }
        if(min != i)
        {
            int swap = values[min];
            values[min] = values[i];
            values[i] = swap;
        }
    }
}

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