crc in c code example

Example: implement crc using c language

#include <stdio.h> #include <conio.h> #include <string.h> void main() {	int i,j,keylen,msglen;	char input[100], key[30],temp[30],quot[100],rem[30],key1[30];	clrscr();	printf("Enter Data: ");	gets(input);	printf("Enter Key: ");	gets(key);	keylen=strlen(key);	msglen=strlen(input);	strcpy(key1,key);	for (i=0;i<keylen-1;i++) {		input[msglen+i]='0';	}	for (i=0;i<keylen;i++)	 temp[i]=input[i];	for (i=0;i<msglen;i++) {		quot[i]=temp[0];		if(quot[i]=='0')		 for (j=0;j<keylen;j++)		 key[j]='0'; else		 for (j=0;j<keylen;j++)		 key[j]=key1[j];		for (j=keylen-1;j>0;j--) {			if(temp[j]==key[j])			 rem[j-1]='0'; else			 rem[j-1]='1';		}		rem[keylen-1]=input[i+keylen];		strcpy(temp,rem);	}	strcpy(rem,temp);	printf("\nQuotient is ");	for (i=0;i<msglen;i++)	 printf("%c",quot[i]);	printf("\nRemainder is ");	for (i=0;i<keylen-1;i++)	 printf("%c",rem[i]);	printf("\nFinal data is: ");	for (i=0;i<msglen;i++)	 printf("%c",input[i]);	for (i=0;i<keylen-1;i++)	 printf("%c",rem[i]);	getch();}