COMP 104 : Programming

Week 3 : Answer


// extra3-1.cpp
// Looping

#include <iostream>
using namespace std;
void main(){
    int r, c;
    for(r=0; r<6; r++){
        for(c=0; c<=r; c++)
            cout << "*";
        cout << endl;
    }
}


// extra3-2.cpp
// Paper, Scissors, Rock plus
#include <iostream>  // contains cout and cin
#include <cstdlib>   // contains the random number generator rand()
#include <ctime>     // contains time() to seed the random number
                     // generator to give a different answer each time
using namespace std;

int main(){
    int userchoice;  // the user's selection
    int computerchoice;  // the computer's selection

    srand(time(0));  // initialize random number generator
    cout << "Paper, Scissors, Rock" << endl;
    while(true){
        computerchoice = rand()%3; // randomly assigns values 0, 1, or 2
        // ask the user for their selection
        do{
            cout << "Enter 0 for paper, 1 for scissors, or 2 for rock: ";
            cin >> userchoice;  // ask the user for their choice

            // print out user's choice (e.g., "Player picks rock")
            // if not 0, 1, or 2, print "Invalid Selection" and quit
            if(userchoice == -1){
                cout << "Game over!" << endl;
                return 0;
            }
            else if(userchoice == 0)
                cout << "Player picks paper" << endl;
            else if(userchoice == 1)
                cout << "Player picks scissors" << endl;
            else if(userchoice == 2)
                cout << "Player picks rock" << endl;
            else
                cout << "Invalid selection, please re-enter." << endl << endl;
        }while(userchoice<-1 || userchoice>2);

        // print out computer's choice (e.g., "Computer picks rock")
        if(computerchoice == 0)
            cout << "Computer picks paper" << endl;
        else if(computerchoice == 1)
            cout << "Computer picks scissors" << endl;
        else
            cout << "Computer picks rock" << endl;

        // print results (either "Draw", "Computer Wins", or "Player Wins")
        if(computerchoice == userchoice)
            cout << "Draw\n";
        else{
            if(computerchoice == 2 && userchoice == 1)
                cout << "Computer Wins\n";
            else if(computerchoice == 1 && userchoice == 0)
                cout << "Computer Wins\n";
            else if(computerchoice == 0 && userchoice == 2)
                cout << "Computer Wins\n";
            else
                cout << "Player Wins\n";
        }
        cout << endl;
    }
    return 0;
}