A general console application programs Day-3

Day3-Console applications Programs

listing 1
// Demonstrate the % operator.

using System;

class ModDemo {  
  public static void Main() {  
    int iresult, irem;
    double dresult, drem;

    iresult = 10 / 3;
    irem = 10 % 3;

    dresult = 10.0 / 3.0;
    drem = 10.0 % 3.0;

    Console.WriteLine("Result and remainder of 10 / 3: " +
                       iresult + " " + irem);
    Console.WriteLine("Result and remainder of 10.0 / 3.0: " +
                       dresult + " " + drem);
  }  
}

listing 2
/*
   Demonstrate the difference between prefix
   postfix forms of ++.
*/
using System;

class PrePostDemo {
  public static void Main() {  
    int x, y;
    int i;

    x = 1;
    Console.WriteLine("Series generated using y = x + x++;");
    for(i = 0; i < 10; i++) {

      y = x + x++; // postfix ++

      Console.WriteLine(y + " ");
    }
    Console.WriteLine();

    x = 1;
    Console.WriteLine("Series generated using y = x + ++x;");
    for(i = 0; i < 10; i++) {

      y = x + ++x; // prefix ++

      Console.WriteLine(y + " ");
    }
    Console.WriteLine();
 
  }
}

listing 3
// Demonstrate the relational and logical operators.

using System;

class RelLogOps {  
  public static void Main() {  
    int i, j;
    bool b1, b2;

    i = 10;
    j = 11;
    if(i < j) Console.WriteLine("i < j");
    if(i <= j) Console.WriteLine("i <= j");
    if(i != j) Console.WriteLine("i != j");
    if(i == j) Console.WriteLine("this won't execute");
    if(i >= j) Console.WriteLine("this won't execute");
    if(i > j) Console.WriteLine("this won't execute");

    b1 = true;
    b2 = false;
    if(b1 & b2) Console.WriteLine("this won't execute");
    if(!(b1 & b2)) Console.WriteLine("!(b1 & b2) is true");
    if(b1 | b2) Console.WriteLine("b1 | b2 is true");
    if(b1 ^ b2) Console.WriteLine("b1 ^ b2 is true");
  }  
}

listing 4
// Create an implication operator in C#.
using System;

class Implication {
  public static void Main() {  
    bool p=false, q=false;
    int i, j;

    for(i = 0; i < 2; i++) {
      for(j = 0; j < 2; j++) {
        if(i==0) p = true;
        if(i==1) p = false;
        if(j==0) q = true;
        if(j==1) q = false;
       
        Console.WriteLine("p is " + p + ", q is " + q);
        if(!p | q) Console.WriteLine(p + " implies " + q +
                    " is " + true);
        Console.WriteLine();
      }
    }
  }
}

listing 5
// Demonstrate the short-circuit operators.

using System;

class SCops {  
  public static void Main() {  
    int n, d;

    n = 10;
    d = 2;
    if(d != 0 && (n % d) == 0)
      Console.WriteLine(d + " is a factor of " + n);

    d = 0; // now, set d to zero

    // Since d is zero, the second operand is not evaluated.
    if(d != 0 && (n % d) == 0)
      Console.WriteLine(d + " is a factor of " + n);
   
    /* Now, try the same thing without short-circuit operator.
       This will cause a divide-by-zero error.  */
    if(d != 0 & (n % d) == 0)
      Console.WriteLine(d + " is a factor of " + n);
  }  
}

listing 6
// Side-effects can be important.

using System;

class SideEffects {  
  public static void Main() {  
    int i;

    i = 0;

    /* Here, i is still incremented even though
       the if statement fails. */
    if(false & (++i < 100))
       Console.WriteLine("this won't be displayed");
    Console.WriteLine("if statement executed: " + i); // displays 1

    /* In this case, i is not incremented because
       the short-circuit operator skips the increment. */
    if(false && (++i < 100))
      Console.WriteLine("this won't be displayed");
    Console.WriteLine("if statement executed: " + i); // still 1 !!
  }  
}

listing 7
//  Use bitwise AND to make a number even.
using System;

class MakeEven {
  public static void Main() {
    ushort num;
    ushort i;  

    for(i = 1; i <= 10; i++) {
      num = i;

      Console.WriteLine("num: " + num);

      num = (ushort) (num & 0xFFFE); // num & 1111 1110

      Console.WriteLine("num after turning off bit zero: "
                        +  num + "\n");
    }
  }
}

listing 8
//  Use bitwise AND to determine if a number is odd.
using System;

class IsOdd {
  public static void Main() {
    ushort num;

    num = 10;

    if((num & 1) == 1)
      Console.WriteLine("This won't display.");

    num = 11;

    if((num & 1) == 1)
      Console.WriteLine(num + " is odd.");

  }
}

listing 9
// Display the bits within a byte.
using System;

class ShowBits {
  public static void Main() {
    int t;
    byte val;

    val = 123;
    for(t=128; t > 0; t = t/2) {
      if((val & t) != 0) Console.Write("1 ");
      if((val & t) == 0) Console.Write("0 ");
    }
  }
}

listing 10
//  Use bitwise OR to make a number odd.
using System;

class MakeOdd {
  public static void Main() {
    ushort num;
    ushort i;  

    for(i = 1; i <= 10; i++) {
      num = i;

      Console.WriteLine("num: " + num);

      num = (ushort) (num | 1); // num | 0000 0001

      Console.WriteLine("num after turning on bit zero: "
                        +  num + "\n");
    }
  }
}

listing 11
// Use XOR to encode and decode a message.

using System;

class Encode {
  public static void Main() {
    char ch1 = 'H';
    char ch2 = 'i';
    char ch3 = '!';

    int key = 88;

    Console.WriteLine("Original message: " +
                      ch1 + ch2 + ch3);

    // encode the message
    ch1 = (char) (ch1 ^ key);
    ch2 = (char) (ch2 ^ key);
    ch3 = (char) (ch3 ^ key);

    Console.WriteLine("Encoded message: " +
                      ch1 + ch2 + ch3);

    // decode the message
    ch1 = (char) (ch1 ^ key);
    ch2 = (char) (ch2 ^ key);
    ch3 = (char) (ch3 ^ key);
 
    Console.WriteLine("Decoded message: " +
                      ch1 + ch2 + ch3);
  }
}

listing 12
// Demonstrate the bitwise NOT.
using System;

class NotDemo {
  public static void Main() {
    sbyte b = -34;
    int t;

    for(t=128; t > 0; t = t/2) {
      if((b & t) != 0) Console.Write("1 ");
      if((b & t) == 0) Console.Write("0 ");
    }
    Console.WriteLine();

    // reverse all bits
    b = (sbyte) ~b;

    for(t=128; t > 0; t = t/2) {
      if((b & t) != 0) Console.Write("1 ");
      if((b & t) == 0) Console.Write("0 ");
    }
  }
}

listing 13
// Demonstrate the shift << and >> operators.
using System;

class ShiftDemo {
  public static void Main() {
    int val = 1;
    int t;
    int i;

    for(i = 0; i < 8; i++) {
      for(t=128; t > 0; t = t/2) {
        if((val & t) != 0) Console.Write("1 ");
        if((val & t) == 0) Console.Write("0 ");
      }
      Console.WriteLine();
      val = val << 1; // left shift
    }
    Console.WriteLine();

    val = 128;
    for(i = 0; i < 8; i++) {
      for(t=128; t > 0; t = t/2) {
        if((val & t) != 0) Console.Write("1 ");
        if((val & t) == 0) Console.Write("0 ");
      }
      Console.WriteLine();
      val = val >> 1; // right shift
    }
  }
}

listing 14
// Use the shift operators to multiply and divide by 2.
using System;

class MultDiv {
  public static void Main() {
    int n;

    n = 10;

    Console.WriteLine("Value of n: " + n);

    // multiply by 2
    n = n << 1;
    Console.WriteLine("Value of n after n = n * 2: " + n);

    // multiply by 4
    n = n << 2;
    Console.WriteLine("Value of n after n = n * 4: " + n);

    // divide by 2
    n = n >> 1;
    Console.WriteLine("Value of n after n = n / 2: " + n);

    // divide by 4
    n = n >> 2;
    Console.WriteLine("Value of n after n = n / 4: " + n);
    Console.WriteLine();

    // reset n
    n = 10;
    Console.WriteLine("Value of n: " + n);

    // multiply by 2, 30 times
    n = n << 30; // data is lost
    Console.WriteLine("Value of n after left-shifting 30 places: " + n);

  }
}

listing 15
// Prevent a division by zero using the ?.
using System;

class NoZeroDiv {
  public static void Main() {
    int result;
    int i;

    for(i = -5; i < 6; i++) {
      result = i != 0 ? 100 / i : 0;
      if(i != 0)
        Console.WriteLine("100 / " + i + " is " + result);
    }
  }
}

listing 16
// Prevent a division by zero using the ?.
using System;

class NoZeroDiv2 {
  public static void Main() {
    int i;

    for(i = -5; i < 6; i++)
      if(i != 0 ? true : false)
        Console.WriteLine("100 / " + i +
                           " is " + 100 / i);
  }
}