sorts prob

[mouse163]

Hi & Happy New Year!!! I was wondering if anyone can tell me why my array sort works ONLY if the array is
less than 11? (making my n double digits 10).
the putput once the array goes greater than 10 gives me a long
negative number at the BEginning of the sort, and if i go MUCH higher than 10 say 20, i get proportionally more of the same negative number.
Hmm just want to know where my bug is.
thanks everyone!
Mouse
ps here is my code

 

#include <iostream.h>
#include<fstream.h> 

void bubble_Sort( int arr[], int n );

ifstream infile("C:\\CODE\\IN.txt"); 
    ofstream outfile("C:\\CODE\\of.txt"); 
 



void main()

{ if(!infile){ 
        cerr << "Cannot open input file" << endl; 
	}

    if(!outfile){ 
        cerr << "Cannot open output file" << endl; 
	}
     



  int arr[10];

 for (int i =0; i< 9; i++)
           infile >> arr[i];

 bubble_Sort( arr, i-1);
  
 for ( i =0; i< 9; i++)
   cout<<"\n"<<arr[i];


}

// Bubble Sort
void bubble_Sort( int arr[], int n)
{
	
   
   
	for (int i=0; i<= n; i++)
		for(int j=0; j<= n-i-1; j++)
			if ( arr[j] > arr[j+1] )
			{	
				int tmp = arr[j+1];
				arr[j+1] = arr[j];
				arr[j] = tmp;
			}	


}

[grib]

int arr[10] in main() is only 10 int's long, if you try to input more it starts writing and working with undefined memory locations.

either make arr bigger or use std::vector<int> and add elements with push_back(). This works a lot like an array, except push_back() makes it get bigger and it always knows it's size.

pass it to buble_sort like this

bubble_sort(std::vector<int> &arr)

you no longer need the n, just use arr.size();

vectors can also sort themselves, but that would be cheating.

[mouse163]

i tried changing the array size[]...AND the n size...
hmm, perhaps i should inveatigate Vectors?
mouse

[Hammer]

http://www.cprogramming.com/cboard/s...threadid=31595