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

// function declarations

FILE *fp_read(char *, int);
double **mem_alloc(int, int);
void zero_array(double **array, int width, int length);
FILE *fp_write(char *, int);

// end function declarations

// functions

// function returns file pointer "w"

FILE *fp_write(char *filename, int str_size){

	FILE *fp;
	
	filename[str_size-1]='\0';
	
	fp=fopen(filename,"w");
	if(!fp){
		printf("Failed to open %s.\nExiting.\n",filename);
		exit(1);
	}
	
	return fp;
}

// zero array

void zero_array(double **array, int width, int length){
	int i, j;
	for(i=0;i<width;i++) for(j=0;j<length;j++) array[i][j]=0.0;
}

// memory allocation for double matrix

double **mem_alloc(int width, int length){
  int i;
  double **result;
  
  result=malloc(width*sizeof(double));
  if(!result){ printf("Memory allocation failure.\n"); exit(1);}

  for(i=0;i<width;i++){ 
    result[i]=malloc(length*sizeof(double));
    if(!result[i]){ printf("Memory allocation failure.\n"); exit(1);}
  }
  return result;
}

// function returns file pointer "r"

FILE *fp_read(char *filename, int str_size){

	FILE *fp;
	
	filename[str_size-1]='\0';
	
	fp=fopen(filename,"r");
	if(!fp){
		printf("Failed to open %s.\nExiting.\n",filename);
		exit(1);
	}
	
	return fp;
}

int main(){
	char filename[40], outfile[40];
	FILE *fp;
	int numcols, numrows;
	int i, j;
	double **data;
	char c;
	double **distance;
	int k;

	system("clear");
	
	printf("Enter the input filename : ");
	fgets(filename,sizeof(filename),stdin);
	
	fp=fp_read(filename,strlen(filename));
	
	printf("Enter ouput filename : ");
	fgets(outfile,sizeof(outfile),stdin);
	
	fscanf(fp,"%d %d",&numcols, &numrows);
	
	data=mem_alloc(numcols,numrows);
	
	// get data
	
	for(i=0;i<numrows;i++)
		for(j=0;j<numcols;j++)
			fscanf(fp,"%lf",&data[j][i]);
	
	// print data for verification
	for(i=0;i<numcols;i++) printf("z_%d   \t",i+1);
	for(i=0;i<numrows;i++){
		printf("\n");
		for(j=0;j<numcols;j++)
			printf("%.4lf\t",data[j][i]);
	}
	printf("\n");
	
	printf("Press ENTER if your data appears correct.\n");
	
	if((c=fgetc(stdin))=='\n')
		system("clear");
	else 
		exit(1);
	
	// calculate distances
	
	distance=mem_alloc(numrows, numrows);
	
	zero_array(distance, numrows, numrows);
	
	for(i=0;i<numrows;i++)
		for(j=0;j<numrows;j++)
			for(k=0;k<numcols;k++)
				distance[i][j]+=pow(data[k][i]-data[k][j],2);
	
	for(i=0;i<numrows;i++)
		for(j=0;j<numrows;j++)
			distance[i][j]=sqrt(distance[i][j]);
			
	fclose(fp);
	
	fp=fp_write(outfile,strlen(outfile));
	
	fprintf(fp,"%d\n\n",numrows);
	
	for(i=0;i<numrows;i++){
		for(j=0;j<numrows;j++)
			fprintf(fp,"%lf\t",distance[i][j]);
		fprintf(fp,"\n");
	}
	
	printf("Distance matrix printed to %s.\n",outfile);
	
	printf("Press ANY KEY to exit.\n");
	
	c=fgetc(stdin);
	
	return 0;

}