Binary to decimal conversion using recursion

// CONVERSION OF BINARY TO DECIMAL USING RECURSION

/*PROCEDURE
   1.Eg:  Take a binary number as 1110
   2.1   1   1 0
       |    |    |    |->multiplyby2^0=result0
               |    |    |->multiply by 2^1  =result1
               |    |->multiply by 2^2  =result2
               |->multiply by 2^3  =result 3

  3.Final ,the converted decimal number=result0+result1+result2+result3

*/


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


int todecimal(char bin[50],int len);
int len; //Using ‘len’ as global variable is optional

void main()
{
char bin[50];
int dec;
clrscr();
printf("Enter the binary number\n");
scanf("%s",bin);
len=strlen(bin);
dec=todecimal(bin,len);
printf("%d",dec);
getch();
}
int todecimal(char bin[50],int l)
{
      if(len-l==len)
return 0;
      else
      {
   if(bin[len-l]=='0')
return todecimal(bin,l-1);
   else
return 1*pow(2,l-1)+todecimal(bin,l-1);
      }
}

Any doubts ask it in comments.
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                             Thank you.