#include #include int main(){ QSet set1; set1 << 1 << 2 << 3 << 4 << 5 << 6; QSet set2; set2 << 4 << 5 << 6 << 7 << 8 << 9; set1.subtract(set2); // output: 1, 2, 3 qDebug() << "set1 remainders:" << set1; return 0;}