Thread: Binary to decimal converter: Bug on greater than 10 digits

Everything works fine until I enter a binary number that has more than 10 digits. In that case, if I enter eleven '1's, sum will equal 1024 (which is the 10th power of 2) and its not adding the rest. I used a print statement to show this. Whats going on?

Code:

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

int main(){
        char number[50];
        puts("Enter Binary Number: ");
        scanf("%s", number);
        int length = strlen(number);
        int remainder = 0, div = 1, idx = 0,    
        array[length], i, l, num = atoi(&number);

        for(i = 1; i < length; i++){
           div *= 10;
        }

        while(num){
           remainder = num/div;
           num = num % div;
           div = div/10;
           array[idx] = remainder;
           idx++;
        }
        int j, n = 1, k = 0, compare[length];
    
        for(j = 1; j <= length; j++){
           compare[k] = n=n>1? n*2:j;
           k++;
        }

       int sum = 0, r = 0;
       for(j = length-1; j >= 0; j--){
          if(array[j] == 1){
              sum += compare[r];
          }
            r++;
       printf("test: %d\n", sum); //<--- test
       }
       printf("Decimal: %d\n", sum);

}

I never got those warnings. Everything complied fine for me, but I made those changes you mentioned anyway.

Originally Posted by atac

I never got those warnings. Everything complied fine for me, but I made those changes you mentioned anyway.

Your compiler sucks. Get something from this century: Code::Blocks

Originally Posted by grumpy

MingW would be sufficient .... it is the compiler that generates warnings, not an IDE like Code::Blocks.

True but Code::Blocks comes with a compiler so I don't have to explain how mingw is installed.

Originally Posted by atac

Whats going on?

You have an integer overflow:

Code:

$ gdb -q ./foo
Reading symbols from foo...done.
(gdb) b 16
Breakpoint 1 at 0x80485f1: file foo.c, line 16.
(gdb) r
Starting program: ./foo 
Enter Binary Number: 
1111111111

Breakpoint 1, main () at foo.c:17
17            while(num){
(gdb) p divisor
$1 = 1000000000
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: ./foo 
Enter Binary Number: 
11111111111

Breakpoint 1, main () at foo.c:17
17            while(num){
(gdb) p divisor
$2 = 1410065408

When you enter a 11-digit binary number your "div" (which I have changed to "divisor") is exceeding the maximum integer value on your system.

Bye, Andreas