C Program to Multiply Two Polynomials

C program to multiply two Polynomial

#include<stdio.h>

#include<conio.h>

#include<stdlib.h>

#include<string.h>

int mult[20];

void display(int a[])

{

  int i;

  for(i=0; i<2*a[0]+1;i++)

  {

    printf("%d, ",a[i]);

  }

  printf("\n");

}

void addpoly(int a[], int b[],int c[])

{

   int i,j,k,temp;

   i=1;j=1;k=1;

   while ((i<=2*a[0]) && (j<=2*b[0])) /* both arrays are existing */

   {

     if (a[i]>b[j])

     {

            c[k]=a[i];

            c[k+1]=a[i+1];

            k=k+2;i=i+2;

     }

     else if (b[j]>a[i])

     {

            c[k]=b[j];

            c[k+1]=b[j+1];

            k=k+2;j=j+2;

     }

     else if (a[i]==b[j])

     {

            temp=a[i+1]+b[j+1];

            if (temp==0)

            {

             i=i+2; j=j+2;

            }

            else

            {

              c[k]=a[i];  /* either a[i] or b[j] can be assigned since both powers are equal */

              c[k+1]=temp;

              k=k+2; j=j+2; i=i+2;

            }

     }

   }

   /* A is not exhausted and B is Exhausted */

   while ( (i<=2*a[0]) && (j>=2*b[0]) )

   {

     c[k]=a[i];

     c[k+1]=a[i+1];

     i=i+2;

     k=k+2;

   }

   /* A is exhausted and B is not Exhausted */

   while ( (i>=2*a[0]) && (j<=2*b[0]) )

   {

     c[k]=b[j];

     c[k+1]=b[j+1];

     j=j+2;

     k=k+2;

   }

   c[0]=k/2;

}

void polymult(int a[], int b[],int mult[])

{

  int d[20], i,j;

  mult[0]=1;mult[1]=-32768;mult[2]=-32768;

  d[0]=1;i=1;j=1;

  display(mult);

  display(d);

  while (i<=2*a[0])

  {

    j=1;

    while (j<=2*b[0])

    {

      d[1]=a[i]+b[j];

      d[2]=a[i+1]*b[j+1];

      j=j+2;

      addpoly(mult,d,mult);

      display(d);

      display(mult);

    }

    i=i+2;

  }

 // c[0]=c[0];

}

void main()

{

  int a[20],b[20],c[20],i;

  clrscr();

  printf("Enter no. of terms in first polynomial\n");

  scanf("%d",&a[0]);

  printf("enter elements in first polynomials i.e. power and coff.\n");

  for(i=1;i<2*a[0]+1; i++)

  {

    scanf("%d",&a[i]);

  }

  printf("Enter no. of terms in Second polynomial\n");

  scanf("%d",&b[0]);

  printf("enter elements in second polynomials i.e. power and coff.\n");

  for(i=1;i<2*b[0]+1; i++)

  {

    scanf("%d",&b[i]);

  }

  display(a);

  display(b);

  /*addpoly(a,b,c);

  printf("Result of Addition of Two Polynomials= \n");

  display(c);*/

  polymult(a,b,mult);

  printf("Result of Multiplication of Twol Polynomials=\n");

  display(mult);

  getch();

}