Mallocing an unsigned char array to store ints
- by Max Desmond
I keep getting a segmentation fault when i test the following code. I am currently unable to find an answer after having searched the web.
a = (byte *)malloc(sizeof(byte) * x ) ;
for( i = 0 ; i < x-1 ; i++ )
{
scanf("%d", &y ) ;
a[i] = y ;
}
Both y and x are initialized. X is the size of the array determined by the user.
The segmentation fault is on the second to last integer to be added, i found this by adding
printf("roar") ; before setting a[i] to y and entering one number at a time.
Byte is a typedef of an unsigned char.
Note: I've also tried using
a[i] = (byte)y ;
A is ininitalized as follows
byte *a ;
If you need to view the entire code it is this:
#include <stdio.h>
#include <stdlib.h>
#include "sort.h"
int p_cmp_f () ;
int main( int argc, char *argv[] )
{
int x, y, i, choice ;
byte *a ;
while( choice !=2 )
{
printf( "Would you like to sort integers?\n1. Yes\n2. No\n" ) ;
scanf("%d", &choice ) ;
switch(choice)
{
case 1:
printf( "Enter the length of the array: " ) ;
scanf( "%d", &x ) ;
a = (byte *)malloc(sizeof( byte ) * x ) ;
printf( "Enter %d integers to add to the array: ", x ) ;
for( i = 0 ; i < x -1 ; i++ )
{
scanf( "%d", &y ) ;
a[i] = y ;
}
switch( choice )
{
case 1:
bubble_sort( a, x, sizeof(int), p_cmp_f ) ;
for( i = 0 ; i < x ; i++ )
printf( "%d", a[i] ;
break ;
case 2:
selection_sort( a, x, sizeof(int), p_cmp_f ) ;
for( i = 0 ; i < x; i++ )
printf( "%d", a[i] ;
break ;
case 3:
insertion_sort( a, x, sizeof(int), p_cmp_f ) ;
for( i = 0 ; i < x ; i++ )
printf( "%d", a[i] ;
break ;
case 4:
merge_sort( a, x, sizeof(int), p_cmp_f ) ;
for( i = 0 ; i < x ; i++ )
printf( "%d", a[i] ;
break ;
case 5:
quick_sort( a, x, sizeof(int), p_cmp_f ) ;
for( i = 0 ; i < x ; i++ )
printf( "%d", a[i] ;
break ;
default:
printf("Enter either 1,2,3,4, or 5" ) ;
break ;
}
case 2:
printf( "Thank you for using this program\n" ) ;
return 0 ;
break ;
default:
printf( "Enter either 1 or 2: " ) ;
break ;
}
}
free(a) ;
return 0 ;
}
int p_cmp_f( byte *element1, byte *element2 )
{
return *((int *)element1) - *((int *)element2) ;
}
