Csharp/C Sharp/Language Basics/Operators

control the operator evaluation sequence

<source lang="csharp"> using System; public class MainClass {

   static void Main(string[] args) {
       int a;
       a = -42;
       Console.WriteLine("{0}", a);
       int b = 2;
       int c = 42;
       a = b * (-c);
       Console.WriteLine("{0}", a);
       c = -42;
       a = b * (+c);
       Console.WriteLine("{0}", a);
   }

}

</source>

Demonstrates compound assignment operators

<source lang="csharp"> /* C# Programming Tips & Techniques by Charles Wright, Kris Jamsa Publisher: Osborne/McGraw-Hill (December 28, 2001) ISBN: 0072193794

• /

// // Assign.cs - Demonstrates compound assignment operators // // Compile this program with the following command line: // C:>csc Assign.cs // namespace nsAssignment {

   using System;
   
   public class Assign
   {
       static public void Main ()
       {
 unsafe
 {
   int x = sizeof (decimal);
   Console.WriteLine ("sizeof decimial = " + x);
 }

// // Start with an integer variable

           int Var = 2;

// // Show the starting value

           Console.WriteLine ("At the beginning, Var = {0}", Var);

// // Multiply the variable by something

           Var *= 12;
           Console.WriteLine ("After Var *= 12, Var = {0}", Var);

// // Add something to the variable

           Var += 42;
           Console.WriteLine ("After Var += 42, Var = {0}", Var);

// // Divide the variable by something

           Var /= 6;
           Console.WriteLine ("After Var /= 6, Var = {0}", Var);

// // Shift the bits in the variable four spaces to the left // This is the same as multiplying by 16 (2 to the fourth power)

           Var <<= 4;
           Console.WriteLine ("After Var <<= 4, Var = {0}", Var);

// // Shift the bits in the variable four spaces to the right using // and expression on the right. This is the same as dividing // by 16.

           int Shift = 3;
           Var >>= Shift + 1;
           Console.WriteLine ("After Var >>= Shift + 1, Var = {0}", Var);

// // Modulo divide the variable by something

           Var %= 6;
           Console.WriteLine ("After Var %= 6, Var = {0}", Var);
       }
   }

}

      </source>

Demonstrate the difference between prefix postfix forms of ++

<source lang="csharp"> /* C#: The Complete Reference by Herbert Schildt Publisher: Osborne/McGraw-Hill (March 8, 2002) ISBN: 0072134852

• /

/*

  Demonstrate the difference between prefix 
  postfix forms of ++. 

• /

using System;

public 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(); 
   
 } 

}

      </source>

Demonstrate the relational and logical operators

<source lang="csharp"> /* C#: The Complete Reference by Herbert Schildt Publisher: Osborne/McGraw-Hill (March 8, 2002) ISBN: 0072134852

• /

// Demonstrate the relational and logical operators.

using System;

public 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"); 
 }    

}

      </source>

Demonstrate the short-circuit operators

<source lang="csharp"> /* C#: The Complete Reference by Herbert Schildt Publisher: Osborne/McGraw-Hill (March 8, 2002) ISBN: 0072134852

• /

// Demonstrate the short-circuit operators.

using System;

public 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); 
 }    

}

      </source>

Illustrates the use of the arithmetic operators

<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110

• /

/*

 Example3_2.csc illustrates the use of
 the arithmetic operators

• /

public class Example3_2 {

 public static void Main()
 {
   // integers and arithmetic operators
   System.Console.WriteLine("10 / 3 = " + 10 / 3);
   System.Console.WriteLine("10 % 3 = " + 10 % 3);
   int intValue1 = 10;
   int intValue2 = 3;
   System.Console.WriteLine("intValue1 / intValue2 = " +
     intValue1 / intValue2);
   System.Console.WriteLine("intValue1 % intValue2 = " +
     intValue1 % intValue2);
   // floats and arithmetic operators
   System.Console.WriteLine("10f / 3f = " + 10f / 3f);
   float floatValue1 = 10f;
   float floatValue2 = 3f;
   System.Console.WriteLine("floatValue1 / floatValue2 = " +
     floatValue1 / floatValue2);
   // doubles and arithmetic operators
   System.Console.WriteLine("10d / 3d = " + 10d / 3d);
   System.Console.WriteLine("10.0 / 3.0 = " + 10.0 / 3.0);
   double doubleValue1 = 10;
   double doubleValue2 = 3;
   System.Console.WriteLine("doubleValue1 / doubleValue2 = " +
     doubleValue1 / doubleValue2);
   // decimals and arithmetic operators
   System.Console.WriteLine("10m / 3m = " + 10m / 3m);
   decimal decimalValue1 = 10;
   decimal decimalValue2 = 3;
   System.Console.WriteLine("decimalValue1 / decimalValue2 = " +
     decimalValue1 / decimalValue2);
   // multiple arithmetic operators
   System.Console.WriteLine("3 * 4 / 2 = " + 3 * 4 / 2);
 }

}

      </source>

Illustrates the use of the bitwise operators

<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110

• /

/*

 Example3_6.cs illustrates the use of
 the bitwise operators

• /

public class Example3_6 {

 public static void Main()
 {
   byte byte1 = 0x9a;  // binary 10011010, decimal 154
   byte byte2 = 0xdb;  // binary 11011011, decimal 219
   byte result;
   System.Console.WriteLine("byte1 = " + byte1);
   System.Console.WriteLine("byte2 = " + byte2);
   // bitwise AND
   result = (byte) (byte1 & byte2);
   System.Console.WriteLine("byte1 & byte2 = " + result);
   // bitwise OR
   result = (byte) (byte1 | byte2);
   System.Console.WriteLine("byte1 | byte2 = " + result);
   // bitwise exclusive OR
   result = (byte) (byte1 ^ byte2);
   System.Console.WriteLine("byte1 ^ byte2 = " + result);
   // bitwise NOT
   result = (byte) ~byte1;
   System.Console.WriteLine("~byte1 = " + result);

   // left shift
   result = (byte) (byte1 << 1);
   System.Console.WriteLine("byte1 << 1 = " + result);
   // right shift
   result = (byte) (byte1 >> 1);
   System.Console.WriteLine("byte1 >> 1 = " + result);
 }

}

      </source>

Illustrates the use of the Boolean logical operators

<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110

• /

/*

 Example3_4.cs illustrates the use of
 the Boolean logical operators

• /

public class Example3_4 {

 public static void Main()
 {
   bool result;
   // use of the Boolean logical AND operator
   result = (1 == 1) && (2 > 1);
   System.Console.WriteLine("(1 == 1) && (2 > 1) is " + result);
   result = (1 == 1) && (2 < 1);
   System.Console.WriteLine("(1 == 1) && (2 < 1) is " + result);
   // use of the Boolean logical OR operator
   result = (1 == 1) || (1 == 0);
   System.Console.WriteLine("(1 == 1) || (1 == 0) is " + result);
   result = (1 == 0) || (1 == 0);
   System.Console.WriteLine("(1 == 0) || (1 == 0) is " + result);
   // use of the Boolean logical NOT operator
   result = !(1 == 0);
   System.Console.WriteLine("!(1 == 0) is " + result);
   result = !(1 == 1);
   System.Console.WriteLine("!(1 == 1) is " + result);
 }

}

      </source>

Illustrates the use of the comparison operators

<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110

• /

/*

 Example3_3.cs illustrates the use of
 the comparison operators

• /

public class Example3_3 {

 public static void Main()
 {
   bool result;
   // false expressions
   result = 10 == 1;
   System.Console.WriteLine("10 == 1 is " + result);
   result = 10 < 1;
   System.Console.WriteLine("10 < 1 is " + result);
   result = 10 <= 1;
   System.Console.WriteLine("10 <= 1 is " + result);
   // true expressions
   result = 10 != 1;
   System.Console.WriteLine("10 != 1 is " + result);
   result = 10 > 1;
   System.Console.WriteLine("10 > 1 is " + result);
   result = 10 >= 1;
   System.Console.WriteLine("10 >= 1 is " + result);
   int intValue1 = 10;
   int intValue2 = 1;
   result = intValue1 != intValue2;
   System.Console.WriteLine("intValue1 != intValue2 is " + result);
 }

}

      </source>

Illustrates the use of the shortcut operators

<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110

• /

/*

 Example3_7.cs illustrates the use of
 the shortcut operators

• /

public class Example3_7 {

 public static void Main()
 {
   int length = 1;
   length += 10;
   System.Console.WriteLine("length = " + length);
   length *= 2;  // multiplies length by 2
   System.Console.WriteLine("length = " + length);
   length /= 3;  // divides length by 3
   System.Console.WriteLine("length = " + length);
 }

}

      </source>

Illustrates the use of the ternary operator

<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110

• /

/*

 Example3_5.cs illustrates the use of
 the ternary operator

• /

public class Example3_5 {

 public static void Main()
 {
   int result;
   result = 10 > 1 ? 20 : 10;
   System.Console.WriteLine("result = " + result);
   result = 10 < 1 ? 20 : 10;
   System.Console.WriteLine("result = " + result);
 }

}

      </source>

Math Operators with int value

<source lang="csharp"> using System; class Operators {

   static void Main() {
       int a, b, c, d, e;
       a = 14;
       b = 15;
       c = 20;
       d = a + b - c; //d=9
       c += d;     //c=29
       e = c + d;   //e=38
       e /= 2;     //e=19
       Console.WriteLine("{0}", e);
   }

}

</source>

Numeric Operators 1

<source lang="csharp"> /*

* C# Programmers Pocket Consultant
* Author: Gregory S. MacBeth
* Email: gmacbeth@comporium.net
* Create Date: June 27, 2003
* Last Modified Date:
* Version: 1
*/

using System; namespace Client.Chapter_2___Operators_and_Excpressions {

 public class NumericOperators1
 {
   static void Main(string[] args)
   {
     int a, b, c, d, e;
     a = 1;
     a += 1;
     b = a;
     b -= 2;
     c = b;
     c *= 3;
     d = 4;
     d /= 2;
     e = 23;
     e %= 3;
   }
 }

}

      </source>

Numeric Operators 3

<source lang="csharp"> /*

* C# Programmers Pocket Consultant
* Author: Gregory S. MacBeth
* Email: gmacbeth@comporium.net
* Create Date: June 27, 2003
* Last Modified Date:
* Version: 1
*/

using System; namespace Client.Chapter_2___Operators_and_Excpressions {

 public class NumericOperators2
 {
   static void Main(string[] args)
   {
     int   a,b,c,d,e,f;
     a = 1;      //1
     b = a + 1;    //2
     b = b - 1;    //1
     c = 1; d = 2;  
     ++c;      //2
     --d;      //1
     e = --c;    // e = 1 c = 1
     f = c--;    // f = 1 c = 0
   }
 }

}

      </source>

Operator precedence

<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110

• /

/*

 Example3_10.cs illustrates operator precedence

• /

public class Example3_10 {

 public static void Main()
 {
   int myInt = 2 + 5 * 10;
   System.Console.WriteLine("2 + 5 * 10 = " + myInt);
   myInt = (2 + 5) * 10;
   System.Console.WriteLine("(2 + 5) * 10 = " + myInt);
   myInt = 2 * 20 / 5;
   System.Console.WriteLine("2 * 20 / 5 = " + myInt);
 }

}

      </source>

Prefix and postfix versions of the increment and decrement operators

<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110

• /

/*

 Example3_8.cs illustrates the use of
 prefix and postfix versions of the
 increment and decrement operators

• /

public class Example3_8 {

 public static void Main()
 {
   // postfix increment
   int length = 3;
   int newLength = length++;
   System.Console.WriteLine("Postfix increment example");
   System.Console.WriteLine("length = " + length);
   System.Console.WriteLine("newLength = " + newLength);
   // prefix increment
   length = 3;
   newLength = ++length;
   System.Console.WriteLine("Prefix increment example");
   System.Console.WriteLine("length = " + length);
   System.Console.WriteLine("newLength = " + newLength);
   // postfix decrement
   length = 3;
   newLength = length--;
   System.Console.WriteLine("Postfix decrement example");
   System.Console.WriteLine("length = " + length);
   System.Console.WriteLine("newLength = " + newLength);
   // prefix decrement
   length = 3;
   newLength = --length;
   System.Console.WriteLine("Prefix decrement example");
   System.Console.WriteLine("length = " + length);
   System.Console.WriteLine("newLength = " + newLength);
 }

}

      </source>

Prevent a division by zero using the ? 1

<source lang="csharp"> /* C#: The Complete Reference by Herbert Schildt Publisher: Osborne/McGraw-Hill (March 8, 2002) ISBN: 0072134852

• /

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

public 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); 
   } 
 } 

}

      </source>

Relational Operators

<source lang="csharp"> /*

* C# Programmers Pocket Consultant
* Author: Gregory S. MacBeth
* Email: gmacbeth@comporium.net
* Create Date: June 27, 2003
* Last Modified Date:
*/

using System; namespace Client.Chapter_2___Common_Type_System {

 public class RelationalOperators
 {
   static void Main(string[] args)
   {
     int a, b;
     a = 1;
     b = 2;
     if (a > b)
       b = 10;
     if (b < a)
       a = 10;
     if (a >= b)
       b = 20;
     if (b <= a)
       a = 20;
     if (a == b)
       b = 5;
     if (b != a)
       b = a;
   }
 }

}

      </source>

Relational Operators 3

<source lang="csharp"> /*

* C# Programmers Pocket Consultant
* Author: Gregory S. MacBeth
* Email: gmacbeth@comporium.net
* Create Date: June 27, 2003
* Last Modified Date:
*/

using System; namespace Client.Chapter_2___Operators_and_Excpressions {

 public class RelationalOperators2
 {
   static void Main(string[] args)
   {
     int a = 10, b = 20, c = 30;
     if (a < 15 && b < 20)
       c = 10;
     if (a < 15 || b < 20)
       c = 15;
     if (!(a == 15))
       c = 25;
   }
 }

}

      </source>

Self decrease

<source lang="csharp"> /* Learning C# by Jesse Liberty Publisher: O"Reilly ISBN: 0596003765

• /

using System;
public class SelfMiValues
{
    static void Main()
    {
        int original = 10;
        int result;
        // increment then assign
        result = --original;
        Console.WriteLine("After prefix: {0}, {1}", original,
            result);
        // assign then increment
        result = original--;
        Console.WriteLine("After postfix: {0}, {1}",
            original, result);
    }
}
          
      </source>

Self increment

<source lang="csharp"> /* Learning C# by Jesse Liberty Publisher: O"Reilly ISBN: 0596003765

• /

using System;
public class SelfValues
{
    static void Main()
    {
        int original = 10;
        int result;
        // increment then assign
        result = ++original;
        Console.WriteLine("After prefix: {0}, {1}", original,
            result);
        // assign then increment
        result = original++;
        Console.WriteLine("After postfix: {0}, {1}",
            original, result);
    }
}
          
      </source>

Side-effects can be important

<source lang="csharp"> /* C#: The Complete Reference by Herbert Schildt Publisher: Osborne/McGraw-Hill (March 8, 2002) ISBN: 0072134852

• /

// Side-effects can be important.

using System;

public 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 !! 
 }    

}

      </source>

Ternary operator

<source lang="csharp"> /* Learning C# by Jesse Liberty Publisher: O"Reilly ISBN: 0596003765

• /

using System;
public class ThreeInputValues
{
    static void Main()
    {
        int valueOne = 10;
        int valueTwo = 20;
        int maxValue = valueOne > valueTwo ?  valueOne : valueTwo;
        Console.WriteLine("ValueOne: {0}, valueTwo: {1}, maxValue: {2}",
            valueOne, valueTwo, maxValue);
    }
}
          
      </source>

The + Operator Is Left Associative

<source lang="csharp">

using System; public class MainClass {

   public static void Main() {
       Console.WriteLine(10 + 25 + "A");   // Same as (10 + 25) + "A", that is "35A" 
       Console.WriteLine("A" + 10 + 25);   // Same as ("A" + 10) + 25, that is "A1025" 
   }

}

</source>