Hamming Distance ErrorDetection And Correction method c implementation

//HAMMING CODE for error detection and correction
#include<stdio.h>
int main()
{
int a[4],b[4],r[3], s[3],i,q[3];
printf("\nenter 4 bit data word:\n");
for(i=3;i>=0;i--)
{
scanf("%d",&a[i]);
}
r[0]=(a[2]+a[1]+a[0])%2;
r[1]=(a[2]+a[1]+a[3])%2;
r[2]=(a[0]+a[1]+a[3])%2;

printf("\n\nthe 7bit hamming code word: \n");
for(i=3;i>=0;i--)
{
printf("%d\t",a[i]);
}
for(i=2;i>=0;i--)
{
printf("%d\t",r[i]);
}
printf("\n");
printf("\nenter the 4bit recieved word: ");

for(i=3;i>=0;i--)
scanf("%d",&b[i]);

//calculating syndrome bits
s[0]= (b[2]+b[1]+b[0]+r[0])%2;
s[1]= (b[3]+b[2]+b[1]+r[1])%2;
s[2]= (b[0]+b[1]+b[3]+r[2])%2;
printf("\nsyndrome is: \n");

for(i=2; i>=0;i--)
{
printf("%d",s[i]);
}
if((s[2]==0) && (s[1]==0) && (s[0]==0))
printf("\n RECIEVED WORD IS ERROR FREE\n");
if((s[2]==1) && (s[1]==0) && (s[0]==1))
printf("\nrecieved word is error with error in 1bit(b0) position from right\n");
if((s[2]==1) && (s[1]==1) && (s[0]==1))
printf("\nrecieved word is error with error in 2bit(b1) position from right\n");
if((s[2]==0) && (s[1]==1) && (s[0]==1))
printf("\nrecieved word is error with error in 3bit(b2) position from right\n");
if((s[2]==1) && (s[1]==1) && (s[0]==0))
printf("\nrecieved word is error with error in 4bit(b3) position from right\n");
return(1);
}
//End of Hamming code program