Conversion from decimal to binary [duplicate]

You can implement a function to do this conversion:

long dec2bin( long dec )
{
    int resto;
    long bin = 0;
    int i = 1;

    while( dec != 0 )
    {
        resto = dec % 2;
        dec /=  2;
        bin += resto * i;
        i *= 10;
    }

    return bin;
}

Code tested:

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

long dec2bin( long dec )
{
    int resto;
    long bin = 0;
    int i = 1;

    while( dec != 0 )
    {
        resto = dec % 2;
        dec /=  2;
        bin += resto * i;
        i *= 10;
    }

    return bin;
}


int main( void )
{
    long i = 0;

    for( i = 0; i < 32; i++ )
        printf( "%ld = %ld\n", i, dec2bin( i ) );

    return 0;
}

Output:

0 = 0
1 = 1
2 = 10
3 = 11
4 = 100
5 = 101
6 = 110
7 = 111
8 = 1000
9 = 1001
10 = 1010
11 = 1011
12 = 1100
13 = 1101
14 = 1110
15 = 1111
16 = 10000
17 = 10001
18 = 10010
19 = 10011
20 = 10100
21 = 10101
22 = 10110
23 = 10111
24 = 11000
25 = 11001
26 = 11010
27 = 11011
28 = 11100
29 = 11101
30 = 11110
31 = 11111