Converting Binary to Octal or Octal to Binary using C

#include<stdio.h>
#include<math.h>
int binary_octal(int n);
int octal_binary(int n);
main()
{
int n;
char c;
printf("Instructions:\n");
printf("1. Enter alphabet 'b' to convert octal to binary.\n");
printf("2. Enter alphabet 'o' to convert binary to octal.\n");
scanf("%c",&c);

if (c =='b' || c == 'B')
{
printf("Enter an octal number: ");
scanf("%d", &n);
printf("%d in octal = %d in binary", n, octal_binary(n));
}

if (c =='0' || c == 'O')
{
printf("Enter a binary number: ");
scanf("%d", &n);
printf("%d in binary = %d in octal", n, binary_octal(n));
}
}

int binary_octal(int n)
{

int octal=0, decimal=0, i=0;
while(n!=0)
{
decimal+=(n%10)*pow(2,i);
++i;
n/=10;
}

i=1;
while (decimal!=0)
{
octal+=(decimal%8)*i;
decimal/=8;
i*=10;
}
return octal;
}

int octal_binary(int n)
{

int decimal=0, binary=0, i=0;
while (n!=0)
{
decimal+=(n%10)*pow(8,i);
++i;
n/=10;
}

i=1;
while(decimal!=0)
{
binary+=(decimal%2)*i;
decimal/=2;
i*=10;
}

return binary;
}