C-Program for Binary to Octal Conversion

#include<stdio.h>
#include<stdlib.h>
main()
{
int b,d,z,r,t,y[50],i,j;
printf("Enter the Binary Number\t");
scanf("%d",&b);
t=b;
z=1;
d=0;
if(b==0)
{
printf("Octal Equivalant of %d is 0",b);
exit(0);
}
while(b>0)
{
r=b%10;
if(r>1)
{
printf("\n Invalid Entry");
exit(0);
}
d=d+(z*r);
z=z*2;
b=b/10;
}
j=0;
while(d>0)
{
r=d%8;
y[j]=r;
j++;
d=d/8;
}
printf("Octal Equivalant of %d is\t",t);
for(i=j-1;i>=0;i--)
printf("%d",y[i]);
} 

output