C program to convert binary to octal

How to convert binary value to octal equivalent?
Binary value 111101100
111101100 => (111) (101) (100) => 754

• Group the binary values(3 digits in each group).
• Find the hexadecimal value for each group and append the outputs.

Write a C program to convert binary value to octal.

  #include <stdio.h>
  #include <string.h>
  #include <math.h>

  /* binary to octal conversion */
  void binaryToOctal(char *data) {
        int i = 0, res = 0, val = 0, count = 2;

        printf("Equivalent Octal Value: ");
        /*
         * find octal value for every 3 digit
         * (start from MSB) and print it
         */
        while (data[i] != '\0') {
                val = val + (data[i] - '0') * pow(2, count);
                i++;
                count--;
                if (i % 3 == 0) {
                        printf("%d", val);
                        val = 0, count = 2;
                }
        }
        printf("\n");
  }

  int main() {

        char input[100], temp[512], ch;

        int value = 0, power = 0, i = 0, j = 0, res, len;

        /* get the binary value from the user */

        printf("Enter your binary value: ");

        fgets(input, 100, stdin);

        input[strlen(input) - 1] = '\0';

        len = strlen(input);

        /* 

         * doing 3 digit alignment for the above obtained binary

         * input.  For example, if the binary input is 1, make

         * it three digit aligned.  001

         */

        if (len % 3 != 0) {

                for (i = len; i >= 0; i--) {

                        input[i + (3 - (len % 3))] = input[i];

                }

                len = 3 - (len % 3);

                while (len > 0) {

                        input[len - 1] = '0';

                        len--;

                }

        }

        /* converting binary to octal value */

        binaryToOctal(input);

        return 0;

  }

  Output:

  jp@jp-VirtualBox:~/$ ./a.out
  Enter your binary value: 111101100
  Equivalent Octal Value: 754