## 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);
}
```
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;
}
```