adding sparse matrices

[budala]

me again

this time i want to add 2 sparse matrices. I define the matrix to have 3 rows and arbitrarily many columns. each row is a linked list and the rows are arranged in an array, so this is sort of a hash table.

the insert method adds elements in each row but does it in a way that all of the elements are sorted. i sort the elements by their column values.

i am having problems adding though. and not always which is puzzling. the program breaks if I have elements in the same position. but also not always. if A has elements in positions (2,2) and B in (2,2) the Add() works great. but if there is more than one element in a row, it breaks,

really frustrating.

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


typedef struct node
	{
		int column;
		int value;
		int row;
		struct node *next;
	} element;

/* MENU */
void Menu()
{
	printf("\n***\tADDING SPARSE MATRICES\t***\n");
	printf("\n 1.) Insert in A");
	printf("\n 2.) Insert in B");
	printf("\n 3.) Printout both");
	printf("\n 4.) A + B = ");
	printf("\n 0.) EXIT");
	printf("\nChoose ---------> ");	
}

/*	Initialize*/
void Init (element *x[])
{
	int i;
	for (i=0; i<3; i++) x[i] = NULL;
}

/*	Printout  */
void Printout (element *x[])
{
	int i, test = 0;
	element *temp;
	
	for (i=0; i<3; i++) 
	{
		temp = x[i];
		while (temp != NULL)
		{
			printf("Element position (%d,%d) = %d\n", i, temp->column, temp->value);
			test = 1;
			temp = temp->next;
		}
	}
	
	if (test == 0) printf("This matrix is empty!!\n");
	
}


/*	INSERT	*/
void Insert(element *x[], int row, int column, int value)
{
	int r = row;
	element *p;
	
	element *new = malloc(sizeof(element));
	new->row = row;
	new->column = column;
	new->value = value;
	
	if (x[r] == NULL) 
	{
		x[r] = new;
		new->next = NULL;
	}
	else
	{
		p = x[r];
		if (new->column < p->column)
		{
			new->next = p;
			x[r] = new;
		}
		else if (new->column > p->column)
		{
			while (p->next != NULL && p->next->column < new->column)
			{
				p = p->next;
			}
			new->next = p->next;
			p->next = new;
		}
		else printf("An element already exists there!!\n");
	}	
}


/*	A  +  B  */
void Add (element *x[],element *y[],element *z[])
{
	int i;
	element *p, *q;
	
	for (i=0; i<3; i++)
	{
		/*row of x empty, row of y not*/
		if (x[i] == NULL && y[i] != NULL)
		{
			q = y[i];
			while (q != NULL)
			{
				Insert(z, i, q->column, q->value);
				q = q->next;
			}
		}
		/*row of y empty, row of x not*/
		if (x[i] != NULL && y[i] == NULL)
		{
			q = x[i];
			while (q != NULL)
			{
				Insert(z, i, q->column, q->value);
				q = q->next;
			}
		}
		/*row of x and y not empty*/		
		if (x[i] != NULL && y[i] != NULL)
		{
			p = x[i];
			q = y[i];
			
			/*stay in while loop until one row runs out*/
			while (p != NULL || q != NULL)
			{
				/*columns match*/
				if (p->column == q->column && p != NULL && q != NULL)
				{
					Insert(z, i, p->column , p->value + q->value);
					p = p->next;
					q = q->next;
				}
				/*column of x is smaller than column of y*/
				else if (p->column < q->column)
				{
					Insert(z, i, p->column , p->value);
					p = p->next;
				}
				/*column of x is bigger than column of y*/
				else
				{
					Insert(z, i, q->column , q->value);
					q = q->next;
				}
			}
			
			/*if row of x had more elements and didn't run out*/
			if (p != NULL)
			{
				while (p != NULL)
				{
					Insert(z, i, p->column , p->value);
					p = p->next;
				}
			}
			/*if row of x had more elements and didn't run out*/
			if (q != NULL)
			{
				while (q != NULL)
				{
					Insert(z, i, q->column , q->value);
					q = q->next;
				}
			}
		}
	}
	
	Printout(z);
}

/*  FREE MEMORY*/
void Freedom (element *x[])
{
	int i;
	element *p;
	for (i=0; i<3; i++)
	{
		if (x[i] != NULL)
		{
		 p = x[i];
		 x[i] = x[i]->next;
		 free(p);
		}
	}
}

/*  MAIN  */
int main (int argc, const char * argv[]) 
{
	int choice, column, row, value, number;
	element *a[3], *b[3], *sum[3];
	Init(a);	Init(b);	Init(sum);		
	do
	{
		Menu();
		scanf("%d",&choice);
		switch (choice)
		{
			case 1:		/*Insert in A */
				do 
				{
					printf("Enter row -> ");
					scanf("%d",&row);
				} while (row < 0 || row > 3);	
			
				do 
				{
					printf("Enter column -> ");
					scanf("%d",&column);
				} while (column < 0);	
				
				printf("Enter value -> ");
				scanf("%d",&value);
				
				Insert(a,row,column,value);
				
				break;
			case 2:		/*Insert in B */
				do 
				{
					printf("Enter row -> ");
					scanf("%d",&row);
				} while (row < 0 || row > 2);	
				
				do 
				{
					printf("Enter column -> ");
					scanf("%d",&column);
				} while (column < 0);	
				
				printf("Enter value -> ");
				scanf("%d",&value);
				
				Insert(b,row,column,value);
				
				break;
			case 3:		/* Printout A & B */
				printf("\n::::::: MATRIX A :> \n\n");
				Printout(a);
				printf("\n::::::: MATRIX B :> \n\n");				
				Printout(b);
				break;
			case 4:		/* A + B */
				Init(sum);
				printf("\n::::::: MATRIX A + B :> \n\n");
				Add(a,b,sum);
				break;
			default:
				printf("\nWRONG CHOICE");
		}
	} while (choice != 0);
	
	

	 Freedom(a);
	 Freedom(b);
	 Freedom(sum);
	return 0;
}

[roaan]

int main (int argc, const char * argv[]) 
{
	int choice, column, row, value, number;
	element *a[3], *b[3], *Add[3];
	Init(a);	Init(b);	Init(sum);		
	do
	{


}

I havent gone through the whole program. But what is the statement

Init(sum); imply

I cant see any variable sum there

are you instead trying to do

Init(Add);

[budala]

you're right. misprint. corrected it