Operator usage in C ++

Operator in C ++ has two usage methods: Operator Overloading operator overload,
One is implicit conversion of operator casting operations.

# Include <iostream> using namespace STD; Class num {protected: int M_a; int m_ B; public: num (int A, int B): M_a (A), m_ B (B) {} num operator + (const num & N) {This-> M_a + = n. m_a; this-> m_ B + = n. m_ B; return * This;} operator bool () {If (this-> M_a = 0 & this-> m_ B = 0) return false; return true ;} /* the input and output operators can only be defined as friend functions */friend ostream & operator <(ostream & OS, num & N) ;}; ostream & operator <(ostream & OS, num & N ){ OS <n. m_a <"," <n. m_ B <Endl; return OS;} int _ tmain (INT argc, _ tchar * argv []) {num A (1, 2); cout <; num B (3, 4); cout <B; A = a + B; cout <A <Endl; if (a) {cout <"! = 0 "<Endl;} return 0 ;}