Thread: beginner help with selection sort

hi all I am trying to use a selection sort on an array but I keep getting a debug error I've never seen before:
"Run Time Check Failure #2- Stack around the variable 'avg' was corrupted." any help is appreciated thanks

Code:

#include<stdio.h>
#include<ctype.h>
#include<stdlib.h>

void averages( int oneTest[ ], int twoTest[ ], int threeTest[ ], int* average1, int* average2, int* average3 );
void selectionSort ( int list[ ], int last );
int main( void )
{
	int avg1, avg2, avg3;

	/*standardDeviation = ( ( count * square ) - ( sum * sum ) ) / ( count * ( count - 1 ) );*/

	int idNum[10] = {0};
	int test1[10] = {0};
	int test2[10] = {0};
	int test3[10] = {0};

	FILE* readThis;
	if ((readThis = fopen ("scores.txt", "r"
		)) ==NULL)  {
			printf("\nError opening file \n");
			exit(101);
	}
	int i = 0;
	while (!feof(readThis))  {
		fscanf( readThis, "%d %d %d %d", &idNum[i], &test1[i], &test2[i], &test3[i] );
		i++;

	}
		fclose(readThis);

	averages( test1, test2, test3, &avg1, &avg2, &avg3 );
	printf("%d\n", test1[9]);
	selectionSort ( test1, test1[9] );
	printf("%d\n", test1[9]);

		return 0;
	}
void averages( int oneTest[ ], int twoTest[ ], int threeTest[ ], int* average1, int* average2, int* average3 )
{
	*average1 = 0;
	*average2 = 0;
	*average3 = 0;

	for( int i = 0; i < 10; i++ ){
		*average1 += oneTest[i];
	}
	
	for( int j = 0; j < 10; j++ ){
		*average2 += twoTest[j];
	}
	
	for( int k = 0; k < 10; k++ ){
		*average3 += threeTest[k];
	}
	
	return;
}
void selectionSort (int list[ ], int last )
{
	int smallest;
	int tempData;

	for( int current = 0; current < last; current++ )
	{
		smallest = current;
		for ( int walk = current + 1; walk <= last; walk++ )
			if ( list[walk] < list [smallest] )
				smallest = walk;

		tempData = list[current];
		list[current] = list[smallest];
		list[smallest] = tempData;
	}

		return;
}

Originally Posted by chelpme

hi all I am trying to use a selection sort on an array but I keep getting a debug error I've never seen before:
"Run Time Check Failure #2- Stack around the variable 'avg' was corrupted." any help is appreciated thanks

Code:

#include<stdio.h>
#include<ctype.h>
#include<stdlib.h>

void averages( int oneTest[ ], int twoTest[ ], int threeTest[ ], int* average1, int* average2, int* average3 );
void selectionSort ( int list[ ], int last );
int main( void )
{
	int avg1, avg2, avg3;

	/*standardDeviation = ( ( count * square ) - ( sum * sum ) ) / ( count * ( count - 1 ) );*/

	int idNum[10] = {0};
	int test1[10] = {0};
	int test2[10] = {0};
	int test3[10] = {0};

	FILE* readThis;
	if ((readThis = fopen ("scores.txt", "r"
		)) ==NULL)  {
			printf("\nError opening file \n");
			exit(101);
	}
	int i = 0;
	while (!feof(readThis))  {
		fscanf( readThis, "%d %d %d %d", &idNum[i], &test1[i], &test2[i], &test3[i] );
		i++;

	}
		fclose(readThis);

	averages( test1, test2, test3, &avg1, &avg2, &avg3 );
	printf("%d\n", test1[9]);
	selectionSort ( test1, test1[9] );
	printf("%d\n", test1[9]);

		return 0;
	}
void averages( int oneTest[ ], int twoTest[ ], int threeTest[ ], int* average1, int* average2, int* average3 )
{
	*average1 = 0;
	*average2 = 0;
	*average3 = 0;

	for( int i = 0; i < 10; i++ ){
		*average1 += oneTest[i];
	}
	
	for( int j = 0; j < 10; j++ ){
		*average2 += twoTest[j];
	}
	
	for( int k = 0; k < 10; k++ ){
		*average3 += threeTest[k];
	}
	
	return;
}
void selectionSort (int list[ ], int last )
{
	int smallest;
	int tempData;

	for( int current = 0; current < last; current++ )
	{
		smallest = current;
		for ( int walk = current + 1; walk <= last; walk++ )
			if ( list[walk] < list [smallest] )
				smallest = walk;

		tempData = list[current];
		list[current] = list[smallest];
		list[smallest] = tempData;
	}

		return;
}

Hi, it might sound odd, but are you sure you are getting that error from this program or there any other programs that are there wihtin in our environment, if you are running in IDE that could be the case, because I tried running this program, it went fine and also one more thing I doubt about the error is, there is no variable named 'avg' in your program, you might want to double check.

Originally Posted by sbattu

Hi, it might sound odd, but are you sure you are getting that error from this program or there any other programs that are there wihtin in our environment, if you are running in IDE that could be the case, because I tried running this program, it went fine and also one more thing I doubt about the error is, there is no variable named 'avg' in your program, you might want to double check.

ah yes you are correct there is no avg in my program I meant to type 'avg1'. So I tried rearranging the variables like this:

Code:

	int idNum[10] = {0};
	int test1[10] = {0};
	int test2[10] = {0};
	int test3[10] = {0};

	int avg1, avg2, avg3;

Interestingly now the same error occurs for idNum, when I press ignore it repeats the same errors for the arrays test1, test2, and test3. The program runs fine in the background I just dont understand this message I am getting. I am a total newbie so can you please explain what you mean by IDE ^^ ty.