dsp. Implementation of General Difference Equation based array mapping C program to implement the difference equation of the LSI system

/* Implementation of General Difference Equation based array mapping
   C program to implement the difference equation of the LSI system
   which is given as

   y(n)=-[a1*y(n-1)+a2*y(n-2)+a3*y(n-3)+......]
+b0*x(n)+b1*x(n-1)+b2*x(n-2)+....

   INPUTS: 1.Number of coefficients ak,denoted as N.
  2.Values of a1,a2,a3,...etc
  3.Number of coefficients bk,denoted as M.
  4.Values of b0,b1,b2,...etc
  5.Number of samples of x(n),denoted as L.
  6.Values of x(0),x(1),x(2),...etc

   OUTPUTS:  The computed output sequence y(n) is according to the specified
    format of difference euation as above.

   ASSUMPTIONS: 1.The number of samples computed for y(n) are same as number
 of input samples.
2.All initial conditions are assumed zero.

   NOTE: Actually there is no specific formula for number of samples in y(n) depend
         upon type of input x(n), coefficients ak and bk and initial conditions.
*/

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

void main()
{
 int N,M,k,L,n;
 float a[10],b[10],x[100],y[100],sum_x,sum_y;

 clrscr();

 printf("\n\t Implementation of General Difference Eqn based array mapping");

 printf("\n\n Enter the number of coefficients a[k]=");
 scanf("%d",&N);              
 printf("\n\n Enter the values coefficients a[k]:\n");

 for(k=1;k<=N;k++)
 {
  printf("a%d=",k);
  scanf("%f",&a[k]);
 }

 printf("\n\n Enter the number of coefficients b[k]=");
 scanf("%d",&M);
 printf("\n\n Enter the values coefficients b[k]:\n");

 for(k=0;k<M;k++)
 {                     // values of b0,b1,b2,....
  printf("b%d=",k);
  scanf("%f",&b[k]);
 }

 printf("\n\n Enter the number of samples of x(n):");
 scanf("%d",&L);

 for(k=0;k<L;k++)
 {                     // values of x(0),x(1),x(2),....
  printf("x(%d)=",k);
  scanf("%f",&x[k]);
 }

 printf("\n The computed values of y(n) are:");
 for(n=0;n<L;n++)
 {
  sum_y=0;
  sum_x=0;

  for(k=1;(k<=n)&&(k<=N);k++)  //computation of a1*y(n-1)+a2*y(n-2)+a3*y(n-3)+..
  {
   sum_y+=a[k]*y[n-k];
  }

  for(k=0;(k<=n)&&(k<=n)&&(k<M);k++)
  {                            //computation of b0*x(n)+b1*x(n-1)+b2*x(n-2)+..

   sum_x+=b[k]*x[n-k];
  }
  y[n]=-sum_y+sum_x;
  printf("\n y(%d)=%f",n,y[n]);
 }
 getch();
}

*op****************


         Implementation of General Difference Eqn based array mapping

 Enter the number of coefficients a[k]=3


 Enter the values coefficients a[k]:

 a1=1
 a2=2
 a3=3


 Enter the number of coefficients b[k]=3


 Enter the values coefficients b[k]:

 b0=3
 b1=2
 b2=1


 Enter the number of samples of x(n):2

 x(0)=1
 x(1)=2

 The computed values of y(n) are:

 y(0)=3.000000
 y(1)=5.000000