1. Math and String Examples

2. The distance between 2 points
The distance between the points (x1,y1) and (x2,y2) is given by the formula:

3. Continued on the next slide
Distance.java
import java.io.*;
public class Distance { public static void main(String[] args) throws IOException { BufferedReader inData = new BufferedReader( new InputStreamReader(System.in)); double x1, y1,x2, y2;
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4. Continued on the next slide
Distance.java
System.out.print("Enter x1: "); x1 = Double.parseDouble(inData.readLine()); System.out.print("Enter y1: "); y1 = Double.parseDouble(inData.readLine()); System.out.print("Enter x2: "); x2 = Double.parseDouble(inData.readLine()); System.out.print("Enter y2: "); y2 = Double.parseDouble(inData.readLine());
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5. Distance.java
double dist = Math.sqrt(Math.pow(x2-x1,2) Math.pow(y2-y1,2));
System.out.println("The distance is “ + dist); } }

6. Output of Distance

7. String class methods
The next example demonstrates the use of the String methods:
length
substring
indexOf
charAt

8. Continued on the next slide
StringDemo.java
import java.io.*;
public class StringDemo { public static void main(String[] args) throws IOException { BufferedReader inData = new BufferedReader( new InputStreamReader(System.in)); String string1, string2, string3;
string1 = "abcdefghijklmnopqrstuvwxyz";
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9. Continued on the next slide
StringDemo.java
System.out.println(string1 + " has " string1.length() + " characters"); int position = string1.indexOf("jkl"); System.out.println("\"jkl\" occurs at " "position " + position " in the string " + string1);
position = string1.indexOf("BOB"); System.out.println("\"BOB\" occurs at " "position " + position " in the string " + string1);
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10. Continued on the next slide
StringDemo.java
string2 = string1.substring(9, 14); System.out.println("string1.substring(9,14) = " string2);
string3 = string1.substring(9); System.out.println("string1.substring(9) = " string3);
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11. StringDemo.java
System.out.println("The character at " "position 5 in the string “ string1 + " is " string1.charAt(5)); } }

12. Output of StringDemo