Solutions I recieved so far on the C riddle

This is a list on the solutions I got from various people on the C riddle, that m3ntor brought up on #demo-gr a couple of days ago.

The riddle goes like this: increment an unsigned int by one in C, without using any of the operators +, -, ++, --, +=, -=, and without any library function calls.

personsolution
m3ntor and samurai 
unsigned int inc(unsigned int num)
{
    return ~num * 0xffffffff;
}
Nuclear 
unsigned int inc(unsigned int num)
{
    return &((char*)num)[1];
}
imak 
unsigned int inc(unsigned int num)
{
    unsigned int w=1, t=num;
    while((t^=w)<num)w<<= 1;
    return t;
}
imak take 2 
unsigned int inc(unsigned int num)
{
    unsigned int a = 0x40000000|(((unsigned int)num)<<23);
    float b = (*((float*)(&a)))*2.0f;
    return (*((unsigned int*)&b)^0x40000000)>>23;
}
xtapodi_kataifi 
unsigned int inc(unsigned int num)
{
    unsigned int y = 1;
    while(num & y) {
        num = num ^ y;
        y = y << 1;
    }
    return num | y;
}
Bartosz Dobrzeleck 
unsigned int inc(unsigned int num)
{
    unsigned int k = 1, l;
    while(k <= num) {
        if((k & num) == 0) {
            l=k;
            while(l > 1) {
                num >>= 1;
                l >>= 1;
            }
            l=k;
            while(l > 1) {
                num <<= 1;
                l >>= 1;
            }
            num |= k;
            return num;
        }
        k <<= 1;
    }
    return k;
}
Peter Simons 
int inc(int i)
{
    return (i&1) == 0 ? i | 1 : inc((unsigned int)i >> 1) << 1;
}