Useful CISS-111 Stuff

File Handling

import java.util.Scanner;
import java.io.FileReader;
import java.io.PrintWriter;

public class files {
  
  public static void main (String[] args) throws FileNotFoundException {
    
    String line, parts[];
    int x;
    Scanner infile = new Scanner(new FileReader("inputfile.txt"));
    PrintWriter outfile = new PrintWriter("outputfile.txt");
    
    while(infile.hasNext()) {
      
      line = infile.nextLine();
      parts = line.split(":");
      for (x = 0; x < parts.length; x++)
        outfile.println(parts[x]);
      
    }
    outfile.close();
    infile.close();
  }
  
}
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Sample input file

thing1:thing2:thing3:thing4:thing5:thing6:thing7:thing8
piece1:piece2:piece4:piece6:piece9:piece12

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Converting Strings and Numbers (SSN Style)

public class Ssn {
  
  public static void main (String[] args) {

    String ssn = "023050089", stringssn;
    int s, f, m, l;
    
    s = Integer.parseInt(ssn);
    
    f = s / 1000000; // 123
    s = s % 1000000; // 456789
    m = s / 10000; // 45
    l = s % 10000; // 6789
    System.out.println("f = " + f);
    System.out.println("m = " + m);
    System.out.println("l = " + l);
    
    System.out.printf("%03d-%02d-%04d%n", f, m ,l);
    stringssn = String.format("%03d-%02d-%04d%n", f, m ,l);
    System.out.printf(stringssn);
  }
}
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Example 2: SSN formatting using integers.

public class Ssn2 {
  
  public static void main (String[] args) {
    // 023050089
    
    String ssn = "023050089", stringssn;
    String f, m, l;
    
    f = ssn.substring(0,3);
    m = ssn.substring(3,5);
    l = ssn.substring(5);
    
    System.out.println("f = " + f);
    System.out.println("m = " + m);
    System.out.println("l = " + l);
    
    stringssn = f + "-" + m + "-" + l;
    System.out.println(stringssn);
  }
}
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Example 3: SSN formatting using String.

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Using split()

public class Split {
  
  public static void main (String[] args) {
    
    String line = "part1:part2:part3:part4:part5";
    String[] parts;
    int x;
    
    parts = line.split(":");
    
    for (x = 0; x < parts.length; x++)
      System.out.println(parts[x]);
  }
}
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Example 4: Using split() to break up a string with delimiters.

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Random numbers

public class Random {
  
  public static void main (String[] args) {
 
    int x, r;
    
    for (x = 1; x <= 10; x++) {
      
      r = (int)(Math.random() * 54 + 45);
      
      System.out.println(r);
    }
  }
}

// 45 -> 98
//-45   -45
//----  ----
//  0    53
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