Number Swapper
16.1 Number Swapper: Write a function to swap a number in place (that is, without temporary variables).
- Notes:
- Math is fun!
// extra space
void swap(int *a, int *b) {
int temp = *(a);
*(a) = *(b);
*(b) = temp;
}
// not safe
void swap2(int *a, int *b) {
*(a + 1) = *(b);
*(b) = *(a);
*(a) = *(a + 1);
}
// safe and inplace
void swap3(int *a, int *b) {
*(a) = *(a)+*(b);
*(b) = *(a)-*(b);
*(a) = *(a)-*(b);
}
int main()
{
int a, b;
a = 1; b = 2;
swap(&a, &b);
cout << a << " " << b << endl;
//swap2(&a, &b);
//cout << a << " " << b << endl;
a = -1; b = 2;
swap3(&a, &b);
cout << a << " " << b << endl;
}
Last modified 4yr ago