Transformando um Binário em Decimal

#include <stdio.h>
#include <stdlib.h>


int multi(int j)
{
int i = j, d, r=1;
for(d=0;d<i;d++){
r = r * 2;
}
return r;
}
int main(int argc, char *argv[])
{
char bin[8];
int i, j, n = 0;
scanf("%s", &bin);
j = (strlen(bin) - 1);
for(i=0;i<=strlen(bin)-1;i++){
if(bin[i] == '1'){
n = (n + multi(j));
}
j--;
}
printf("\n%d\n", n);
system("PAUSE");
return 0;
}