MODULE 2 - SHEET 1


public class ComeIn
 { public static void main(String[] args)
    { System.out.println("Come in number 57 please");
    }
 }


public class ComeAgain
 { private static int n;

   public static void main(String[] args)
    { n = 57;
      System.out.println("Come in number " + n + " please");
    }
 }


public class ComeFinal
 { public static void main(String[] args)
    { int n;
      n = 57;
      System.out.println("Come in number " + n + " please");
    }
 }


public class TwiceA
 { public static void main(String[] args)
    { int i, j;
      i = 57;
      j = 2*i;
      System.out.println("Twice " + i + " is " + j);
    }
 }


public class TwiceB
 { public static void main(String[] args)
    { int i, j;
      i = 57;
      j = twice(i);
      System.out.println("Twice " + i + " is " + j);
    }

   private static int twice(int m)
    { int n;
      n = 2*m;
      return n;
    }
 }


public class TwiceC
 { public static void main(String[] args)
    { int i = 57;
      System.out.println("Twice " + i + " is " + twice(i));
    }

   private static int twice(int k)
    { return 2*k;
    }
 }


public class ArgsArrayA
 { public static void main(String[] args)
    { System.out.println("There are " + args.length + " arguments");
      System.out.println(args[0] + " " + args[1] + " " + args[2]);
    }
 }

// When run as  java ArgsArrayA Tom Dick Harry  this yields:
//
// There are 3 arguments
// Tom Dick Harry
//
// When run as  java ArgsArrayA  this yields:
//
// There are 0 arguments
//
// and then throws an  ArrayIndexOutOfBoundsException


MODULE 2 - SHEET 2

Some Java Constructs Loops: If Statements: while (<condition>) if (<condition>) <statement> { <statement> <statement> <statement> if (<condition>) } { <statement> <statement> <statement> do } { <statement> <statement> <statement> if (<condition>) } while (<condition>); { <statement> <statement> <statement> while (true) } { <statement> else <statement> { <statement> <statement> <statement> } <statement> } for (<initialize>; <check>; <update>) { <statement> <statement> <statement> } Ternary if-else operator: <condition> ? <true-value> : <false-value> Relational Operators: < <= > >= == != Reserved Words: abstract default goto operator synchronized boolean do if outer this break double implements package throw byte else import private throws byvalue extends inner protected transient case false instanceof public true cast final int rest try

MODULE 2 - SHEET 3

public class SumA { public static void main(String[] args) { int sum=0, i=1; while (i<=100) { sum = sum+i; i = i + 1; } System.out.println("Sum is " + sum); } } public class SumB { private static int n=100; public static void main(String[] args) { int sum=0, i=1; while (i<=n) { sum = sum+i; i = i + 1; } System.out.println("Sum is " + sum); } } public class SumC { private static int n=100; public static void main(String[] args) { int sum=0, i=1; do { sum += i; i += 1; } while (i<=n); System.out.println("Sum is " + sum); } } public class SumD { private static int n=100; public static void main(String[] args) { int sum=0, i=1; while (true) { sum += i; if (i==n) { break; } i++; } System.out.println("Sum is " + sum); } } public class SumE { private static final int N=100; public static void main(String[] args) { int sum=0; for (int i=1; i<=N; i++) { sum += i; } System.out.println("Sum is " + sum); } } public class ArgsArrayB { public static void main(String[] args) { System.out.println("There are " + args.length + " arguments"); for (int i=0; i<args.length; i++) System.out.print(args[i] + " "); System.out.println(); } }

MODULE 2 - SHEET 4

public class ArrayIntro { public static void main(String[] args) { int k = 1; int[] jack; // To save a line write: jack = new int[4]; // int[] jack = new int[4]; jack[1] = 10; jack[3] = jack[1] - 5; jack[0] = jack[3]; jack[k+1] = 6; int sum = 0; for (int i=0; i<4; i++) sum += jack[i]; System.out.println("Total is " + sum); int[] jill = {3,1,4,1,5,9}; System.out.println("Length is " + jill.length); sum = 0; for (int i=0; i<jill.length; i++) sum += jill[i]; System.out.println("Total is " + sum); jack = jill; } } public class SumArr { public static void main(String[] args) { int[] tom = {6,2,1,4,3,5}; System.out.println("Total of tom is " + sum(tom)); } private static int sum(int[] a) { int s = 0; for (int i=0; i<a.length; i++) s += a[i]; return s; } }