Random Numbers, Games, and Simulation - Advanced Topics in Java: Core Concepts in Data Structures - page 169

All the details are shown in Program P6.3. In the interest of brevity, we have not validated the input provided by
the user. However, it is strongly recommended that all user input be validated to ensure that your programs are as
robust as possible.
Program P6.3
import java.util.*;
public class Arithmetic {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
System.out.printf("\nWelcome to Problems in Addition\n\n");
System.out.printf("How many problems would you like? ");
int numProblems = in.nextInt();
System.out.printf("Maximum tries per problem? ");
int maxTries = in.nextInt();
giveProblems(in, numProblems, maxTries);
System.out.printf("\nThank you for playing. Bye...\n");
} //end main
public static void giveProblems(Scanner in, int amount, int maxTries) {
int num1, num2, answer, response, tri; //'tri' since 'try' is a reserved word
for (int h = 1; h <= amount; h++) {
num1 = random(10, 99);
num2 = random(10, 99);
answer = num1 + num2;
for (tri = 1; tri <= maxTries; tri ++) {
System.out.printf("\nProblem %d, Try %d of %d\n", h, tri, maxTries);
System.out.printf("%5d + %2d = ", num1, num2);
response = in.nextInt();
if (response == answer) {
System.out.printf("Correct, well done!\n");
break;
}
if (tri < maxTries) System.out.printf("Incorrect, try again\n");
else System.out.printf("Sorry, answer is %d\n", answer);
} //end for tri
} //end for h
} //end giveProblems
public static int random(int m, int n) {
//returns a random integer from m to n, inclusive
return (int) (Math.random() * (n - m + 1)) + m;
} //end random
} //end class Arithmetic
6.6 Nim
One version of the game called Nim is played between two people, A and B, say. Initially, there is a known number of
matches ( startAmount , say) on the table. Each player, in turn, is allowed to pick up any number of matches from 1 to
some agreed maximum ( maxPick , say). The player who picks up the last match loses the game.