mathops.java

the souce code of thinking in java (1-10),if you want to learn java ,please read it and you will get

//: c03:MathOps.java
// Demonstrates the mathematical operators.
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
import com.bruceeckel.simpletest.*;
import java.util.*;

public class MathOps {
  static Test monitor = new Test();
  // Shorthand to print a string and an int:
  static void printInt(String s, int i) {
    System.out.println(s + " = " + i);
  }
  // Shorthand to print a string and a float:
  static void printFloat(String s, float f) {
    System.out.println(s + " = " + f);
  }
  public static void main(String[] args) {
    // Create a random number generator,
    // seeds with current time by default:
    Random rand = new Random();
    int i, j, k;
    // Choose value from 1 to 100:
    j = rand.nextInt(100) + 1;
    k = rand.nextInt(100) + 1;
    printInt("j", j);  printInt("k", k);
    i = j + k; printInt("j + k", i);
    i = j - k; printInt("j - k", i);
    i = k / j; printInt("k / j", i);
    i = k * j; printInt("k * j", i);
    i = k % j; printInt("k % j", i);
    j %= k; printInt("j %= k", j);
    // Floating-point number tests:
    float u,v,w;  // applies to doubles, too
    v = rand.nextFloat();
    w = rand.nextFloat();
    printFloat("v", v); printFloat("w", w);
    u = v + w; printFloat("v + w", u);
    u = v - w; printFloat("v - w", u);
    u = v * w; printFloat("v * w", u);
    u = v / w; printFloat("v / w", u);
    // the following also works for
    // char, byte, short, int, long,
    // and double:
    u += v; printFloat("u += v", u);
    u -= v; printFloat("u -= v", u);
    u *= v; printFloat("u *= v", u);
    u /= v; printFloat("u /= v", u);
    monitor.expect(new String[] {
      "%% j = -?\\d+",
      "%% k = -?\\d+",
      "%% j \\+ k = -?\\d+",
      "%% j - k = -?\\d+",
      "%% k / j = -?\\d+",
      "%% k \\* j = -?\\d+",
      "%% k % j = -?\\d+",
      "%% j %= k = -?\\d+",
      "%% v = -?\\d+\\.\\d+(E-?\\d)?",
      "%% w = -?\\d+\\.\\d+(E-?\\d)?",
      "%% v \\+ w = -?\\d+\\.\\d+(E-?\\d)??",
      "%% v - w = -?\\d+\\.\\d+(E-?\\d)??",
      "%% v \\* w = -?\\d+\\.\\d+(E-?\\d)??",
      "%% v / w = -?\\d+\\.\\d+(E-?\\d)??",
      "%% u \\+= v = -?\\d+\\.\\d+(E-?\\d)??",
      "%% u -= v = -?\\d+\\.\\d+(E-?\\d)??",
      "%% u \\*= v = -?\\d+\\.\\d+(E-?\\d)??",
      "%% u /= v = -?\\d+\\.\\d+(E-?\\d)??"
    });
  }
} ///:~