/* pascalstriangle.c */

/* © Copyright 2003 Dauger Research, Inc. 
    
Our lawyers made us say this: 
DISCLAIMER: We provide the following on an "AS IS" basis. Use it at your own risk.  */

#include <stdio.h> /* standard I/O routines */
#include <stdlib.h> /* standard library routines, such as memory */
#include <math.h> /* math libraries */

#define myType		unsigned long

/* Routines performing elemental work. */
void addright(myType *inputArray, long size); 
void addright(myType *inputArray, long size) 
	{
	if (inputArray) {
		long i=size-1; 
		while (i--) 
			inputArray[i+1]+=inputArray[i]; 
		}
	}

void addleft(myType *inputArray, long size); 
void addleft(myType *inputArray, long size) 
	{
	if (inputArray) {
		long i; 
		for(i=0; i<size-1; i++) 
			inputArray[i]+=inputArray[i+1]; 
		}
	}

void iterationloop(myType *theArray, long arraySize, long lastIteration, short verbose); 
void iterationloop(myType *theArray, long arraySize, long lastIteration, short verbose)
	{
	/* limit of the loop */
	
	/* allocate an array to hold all the results */
	
	if (theArray) if (arraySize>0) {
		long index; 
		
		/* loop over indicies */
		for(index=0; index<lastIteration; index++) {
			/* call the left or right routine for each index, reusing array */
			if (1&index) {
				addleft(theArray, arraySize); 
				}
			else {
				addright(theArray, arraySize); 
				}
			
			if (verbose) {long i; 
				for(i=0; i<arraySize; i++) {
					if (1&verbose) 
						printf("%d\t", theArray[i]); 
					else 
						printf("%c", theArray[i]&1?'*':' '); 
					}
				printf("\n"); 
				}
			}
		
		}
	
	}
	
/* BinomalExponent specifies how far to propagate */

void computeloop(myType **theArray, long binomalExponent); 
void computeloop(myType **theArray, long binomalExponent)
	{
	/* local copies of the data to be output */
	myType *myArray; 
	long arraySize=binomalExponent+1; 
	
	/* allocate an array to hold all the results */
	myArray=malloc(sizeof(myType)*arraySize); 
	
	if (myArray) {
		long i; 
		
		/* clear the array */
		for(i=arraySize; i--; )
			myArray[i]=0; 
		
		/* seed the array */
		myArray[binomalExponent>>1]=1; 
		
		/* propagate */
		iterationloop(myArray, arraySize, binomalExponent, 2); 
		}
	
	/* return the array */
	*theArray=myArray; 
	}
	
#define BinomalExponent			30L

int main(int argc, char *argv[])
	{
	/* main copies of the sum and the array */
	myType *theArray=NULL; 
	
	printf("Beginning computation...\n"); 
	
	computeloop(&theArray, BinomalExponent); 
	
	if (theArray) {/* error checking */
		FILE *fp; 
		
		/* save the array into a data file */
		fp=fopen("output", "w"); 
		if (fp) {
			printf("writing array...\n"); 
			
			fwrite(theArray, sizeof(myType), BinomalExponent+1, fp); 
			
			fclose(fp); 
			}
		
		if (1) 	{long i; 
			for(i=0; i<BinomalExponent+1; i++) 
				printf("%d\t", theArray[i]); 
			printf("\n"); 
			}
		
		/* clean up after myself */
		free(theArray); 
		
		}
	else 
		printf("memory allocation failure\n"); 
	
	return 0; 
	}