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


#define MAX 2000000

FILE *pFile[5];
char filename[5][25];


double scale;
double f[MAX],a[MAX];

long i,last;

int nn;

void main()
{
    printf("\n decimate_nf.cpp  ver 1.0  \n");
	printf("\n by Tom Irvine  Email: tomirvine@aol.com \n");

	printf("\n Decimation with no pre-filtering. \n");
	
	printf("\n Enter decimation integer. \n");
	scanf("%d",&nn);

	
 	printf( "\n\n The base input file must contain two columns: \n");
	printf( " time(sec)  amplitude    \n");

	printf( "\n Enter input filename \n");
	scanf("%s",filename[0]);
	
    pFile[0] = fopen(filename[0], "rb");


	if(pFile[0] == NULL )
	{
      printf(" Failed to open file: %s \n", filename[0]);
	}
	else
	{
      printf(" File: %s opened. \n", filename[0]);
	}


	printf( "\n Enter output filename \n");
	scanf("%s",filename[1]);
	
    pFile[1] = fopen(filename[1], "w");


   i=0;
   while( fscanf(pFile[0], "%lf %lf", &f[i], &a[i]) > 0 )
   {
      i++;

	  if(i==MAX){break;}
   }
   fclose(pFile[0]);

   last=i;

   printf("\n\n %ld samples read \n",last);


   for(i=0; i<last; i+=nn)
   {
		fprintf(pFile[1],"%12.7e \t %12.6e\n",f[i],a[i] ); 
   }

		
	printf("\n\n Calculation complete. \n\n Press any key to exit.");
	getch();
}