When you want to do a test against true or false with a integer value. Basically 0 is false and anything else is true, as demonstrated below.
#include <stdlib.h> #include <iostream> using namespace std; int main() { for (int i = -10; i < 10; i++) { if (i) cout << "true " << i << endl; else cout << "false " << i << endl; } } |
and the output of this is, the true/false values is after the if statement.
true -10 true -9 true -8 true -7 true -6 true -5 true -4 true -3 true -2 true -1 false 0 true 1 true 2 true 3 true 4 true 5 true 6 true 7 true 8 true 9 |