Random Number Generation

Pseudo-Random Generation

rand() #include <iostream> using namespace std; int main() { for(int i = 1; i <= 10; i++) cout << rand() << endl; return 0; }

rand() First Execution #include <iostream> using namespace std; int main() { for(int i = 1; i <= 10; i++) cout << rand() << endl; return 0; } 38457 733887 7384 94877 243 3994452 374008 23146 11833432 237844

rand() First Execution Second Execution #include <iostream> using namespace std; int main() { for(int i = 1; i <= 10; i++) cout << rand() << endl; return 0; } 38457 733887 7384 94877 243 3994452 374008 23146 11833432 237844 38457 733887 7384 94877 243 3994452 374008 23146 11833432 237844

srand() #include <iostream> #include <ctime> #include <cstdlib> using namespace std; int main() { srand(time(NULL)); for(int i = 1; i <= 10; i++) cout << rand() << endl; return 0; }

srand() First Execution #include <iostream> #include <ctime> #include <cstdlib> using namespace std; int main() { srand(time(NULL)); for(int i = 1; i <= 10; i++) cout << rand() << endl; return 0; } 464 53735 342 23 6578 889 93723 7165 7422457 78614

srand() First Execution Second Execution #include <iostream> #include <ctime> #include <cstdlib> using namespace std; int main() { srand(time(NULL)); for(int i = 1; i <= 10; i++) cout << rand() << endl; return 0; } 464 53735 342 23 6578 889 93723 7165 7422457 78614 6877 245768 215 57618 78511 79738 3461 175117 35 257868

limiting range: [0, MAX_RAND] #include <iostream> #include <ctime> #include <cstdlib> using namespace std; int main() { long next_value; srand(time(NULL)); for (int i = 1; i <= 100000; i++) if (rand()%100 <= 34) cout << "hello" << endl; // ~35,000 times else cout << "goodbye" << endl; // ~65,000 times return 0; }

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