0
#include <stdio.h>
#include <cs50.h>

int main(void)
{
int values[12] = {10,2,14,5,7,4,3,13,15,22,8,24};
int i = 0;
int n = 12;   
for(int x = 0; x < n*n; x++)
{
    while(i<n-1)
    {

        if(values[i]>values[i+1])
        {
          int temp = values[i+1];
          values[i+1] = values[i];
          values[i] = temp;
          i++;
          for(int c = 0; c < n; c++)
          {
           printf("%i ",values[c]);
          }
          for(int a = 0; a < 1; a++)
          {
           printf("\n");
          }

        }

        else
        {
        i++;
        }

    }
    while(i >= 5) 
    {
    i=0;
    }   
}
}

So this is basically my bubble sort algorithm. And as it seems it works fine. While implementing it in helpers.c. i use n as a number of how long is array values, and values as an array.

This is how it looks:

/**
 * 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)
{
    // TODO: implement a searching algorithm
    if(n < 0)
     {
     return false;
     }
     else
    {
      for(int i = 0; i < n; i++)
      {
        if(values[i]==value)
        {
        return true;
        }
      }
    }
    return false;
}

/**
 * Sorts array of n values.
 */
void sort(int values[], int n)
{
    int i = 0;
    // TODO: implement an O(n^2) sorting algorithm
    for(int x = 0; x < n*n; x++)
    {
    while(i<n-1)
    {

        if(values[i]>values[i+1])
        {
          int temp = values[i+1];
          values[i+1] = values[i];
          values[i] = temp;
          i++;
          for(int c = 0; c < n; c++)
          {
           printf("%i ",values[c]);
          }
          for(int a = 0; a < 1; a++)
          {
           printf("\n");
           }

        }

        else
        {
         i++;
        }

     }
     while(i >= 5) 
     {
     i=0;
    }   
    }

 }

And then i run ./generate 1000 50 | ./find 127 haystack[996] = haystack[997] = haystack[998] = haystack[999] = haystack[1000] =

Found needle in haystack!

I get his... Haystacks are empty, and sort seems is not executed... How i need to run it or change it for it to work?

3
  • hi, @Vienas Du! you probably need to work more on the style of your code. see manual.cs50.net/style for tips! I don't see why you're iterating n * n times. also, I'm not sure why you're wrapping printf("\n") in a for loop that iterates once, why you're resetting i to 0 when it's > 5. did you see the pseudocode of bubble sort here? – kzidane Mar 18 '16 at 22:07
  • n * n is done because maximum times it can go around is O(n2), so if array is 8 long, maximum times it could be going is 8*8. for loop iterates every time while loop is run, so it basically prints all array in the new line every time it is printed. 5 it just random number because it basically its only called then first while is false, it could be any number. Even if my algorithm is wrong i need help to how to implement it. I will modify it later, but i just cant get it working in helpers.c – Vienas Du Mar 19 '16 at 0:13
  • I mean then i try to get make find i get this error: helpers.c:57:12: error: implicitly declaring library function 'printf' with type 'int (const char *, ...)' [-Werror] printf("%c ",values[c]); – Vienas Du Mar 19 '16 at 0:20
0

I believe the problem is a lack of understanding on how it runs when you execute it this way. It appears that you're concerned that none of the numbers in the haystack are appearing on the screen and you aren't sure whether the sort is running.

"And then i run ./generate 1000 50 | ./find 127" When you execute the program this way, you have to understand what's happening. /find is writing all of it's printf() calls to the screen, but instead of taking the input from the console (keyboard), it is taking input from the piped output generated by ./generate. The numbers are going directly into find from generate, and will not be printed to the screen.

If you're worried that sort isn't working, you could add a small loop to simply print out the haystack array from element 0 in order. If the list was input to the program out of order and the output list is sorted, then it's working. You could go a step further and add code to check that any number in the list is equal to or larger than the previous number.

Unfortunately, my IDE is down, so I can't test.

If this answers your question, please click on the check mark to accept. Let's keep up on forum maintenance. ;-)

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