character array of bitstring

character array of bitstring

for(i = 0; bitstr[i] != '\0'; i++){
if(!(bitstr[i]=='0' || bitstr[i]=='1')){
printf("Not a valid bitstring!");
exit(0);
}
else{
sum = sum*2+bitstr[i];
}
}
printf("%d", sum);
When I enter 101 for instance, it prints 339, when it should print 3 as
the answer. I am not sure what I am doing wrong. Any help would be much
appreciated.