C Program to implement Checksum

/* CHECKSUM */



#include<stdio.h>

#include<conio.h>



void main()

{

 int a[4], b[4], s_check, r_check, s_sum=0, r_sum=0;

 int i;

 clrscr();



 printf("\n----SENDER----");

 printf("\nEnter the values in hex: ");

 for(i=0;i<4;i++)

 {

  scanf("%x", &a[i]);

 }



 printf("\nEnter checksum: ");

 scanf("%x", &s_check);



 for(i=0; i<4; i++)

 {

  s_sum=s_sum+a[i];

 }

 s_sum=s_sum+s_check;

 printf("\nThe sum is %x", s_sum);

 s_sum=s_sum+1;

 s_sum=~s_sum;

 printf("\nThe checksum generated is %x", s_sum);



 printf("\n----RECEIVER----");

 printf("\nEnter the values in hex: ");

 for(i=0;i<4;i++)

 {

  scanf("%x", &b[i]);

 }



 printf("\nEnter checksum: ");

 scanf("%x", &r_check);



 for(i=0; i<4; i++)

 {

  r_sum=r_sum+b[i];

 }

 r_sum=r_sum+r_check;

 printf("\nThe sum is %x", r_sum);

 r_sum=r_sum+1;

 r_sum=~r_sum;

 printf("\nThe checksum generated is %x", r_sum);



 if(r_sum==0000)

  printf("\nNo Error in Transmission");

 else

  printf("\nError!");





 getch();

}



/* OUTPUT





----SENDER----

Enter the values in hex: 466f 726f 757a 616e



Enter checksum: 0000



The sum is 8fc6

The checksum generated is 7038

----RECEIVER----

Enter the values in hex: 466f 726f 757a 616e



Enter checksum: 7038



The sum is fffe

The checksum generated is 0

No Error in Transmission

*/