1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 #include <iostream> #include <iomanip> #include <sstream> using namespace std; class hello { unsigned int limit; exec(); exec(int i); string greet; public: hello(); operator=(unsigned int i); run(); run(int i); }; hello::exec() { cout << greet << endl; } hello::exec(int i) { cout << "[" << setfill('0') << setw(4) << i << "] "; exec(); } hello::hello() { limit=10; greet = "Hello World."; } hello::operator=(unsigned int i) { if(i>0) limit=i; } hello::run() { run(1); } hello::run(int i) { if(i<=limit) { exec(i); i++; run(i); } } int main(int argc, char *argv[]) { hello world; if(argc>1) { stringstream ss(argv[1]); int i; ss >> i; world = i; } world.run(); return 0; }
This Hello World program, illustrates a number of object oriented programming features of C++; including use of classes, method and operator overloading and recursive functions.