int add(int a, int b){
if(!a) return b;
return add((a & b) << 1, a ^ b);
}
int i = 100;
do{
//something
}while(i --> 0);
int a[5] = {1, 2, 3, 4, 5};
for(int i = 0;i < 5;i++){
printf("%d\n", i[a]);
printf("%d\n", (i - 1)[a + 1]);
}
int num = 11;
printf("%d\n", num % 2 == 0);
printf("%d\n", num & 1);
0xffffffff
x <<= 1; //x *= 2
x >>= 1; //x /= 2
x = (x << 1) + (x << 3); //x *= 10
int a = 2,b = 3;
a ^= b;
b ^= a;
a ^= b;
//or
a^=b^=a^=b
a ≠ b <=> a ^ b
int a, b;
char ch;
ch = a ^ 48;
b = ch ^ 48;