'&&' and '||' are what's called "short-circuiting" logical operators.
In the case of &&, if the first operand is false, then it doesn't bother evaluating the second operand, because the whole expression is certain to be false.
In the case of ||, if the first operand is true, then it doesn't bother evaluating the second operand, because the whole expression is certain to be true.
'&' and '|' can also be used as logical operators though it's more common for them to be used as bitwise operators. When they're used as logical operators, both operands are always evaluated.
Thanks,
Krunal
Please Mark as answer if it helps.it will help others to find the solution.
Marked as answer by Figo Fei - MSFT on Aug 13, 2009 09:31 AM
The && is the Conditional AND Operator and is used to evalute if multiple statements are true using the if statement (or false depending on what you're testing for)
int x = 3;
int y = 7;
if( (x==3) && (y==7))
{
//some command here
}
This statement would evaluate to True since x really does equal 3 and y really does equal 7. (because we set them to those values).
The & is the Logical AND Operator and as far as I can tell operates the same as the above, though this one appears to take a
higher priority.
Hope that helps, I referenced O'Reilly Learning C# 2005 pg. 66-68 and this link http://visualcplus.blogspot.com/2006/02/lesson-8-conditional-and-logical.html
Remeber to Mark As Answer if this is the solution you were looking for.
&& (double ampersand), || (double pipe), & (single ampersand), | (single pipe) and ^ (carat symbol) all operate on the same principal. i.e. use truth table for the execution. See below for the truth table.
&& (double ampersand) and || (double pipe) are conditional operators. These two operators are used to compare two results' boolean value and hence decide on the next course of action.
bool firstCondition = true;
bool secondCondition = true;
// The code block following the if condition is executed only if firstCondition and
// secondCondition both are true. Otherwise, the if block is skipped.
if(firstCondition && secondCondition)
{
//Do Something;
}
// The code block following the if condition is executed if either the right hand operand // or left hand operand is true.
if(firstCondition || secondCondition)
{
//Do Something;
}
Remember the following truth table.
T -> Truth
F -> False
AND can be either && or &
and OR can be either || or |
Truth Tables
X AND Y -> Result
---------------------
T AND T -> T
T AND F -> F
F AND T -> F
F AND F -> F
X OR Y -> Result
---------------------
T OR T -> T
T OR F -> T
F OR T -> T
F OR F -> F
As you see from the result, && results to false when either of the operand is false, whereas || results to truth when either of the operands is true.
& (single ampersand), | (single pipe) and ^ (Used for XOR in C#) are called as bitwise operators. Because they operate on bits instead of on conditions.
For eg. if X = 4 and Y =3
The resultant value for
X & Y = 4 & 3 = 0
X | Y = 4 | 3 = 7
This is because, the bitwise operators work on bits instead of on conditions...
So 4 in binary is 0100 and 3 in binary is 0011 - and remember from the truth table "and" operator results into "true" only when both the operands are true otherwise false. So
0 1 0 0
& 0 0 1 1
---------
0 0 0 0 -> because 0 => false and 1 => true
0 1 0 0
| 0 0 1 1
-----------
0 1 1 1 -> and when we convert 0111 from binary to decimal we get 7.
int a = 10;
int b = 20;
int c = a & b;
Console.WriteLine ("The value of 'a' is " + a);
Console.WriteLine ("The value of 'b' is " + b);
Console.WriteLine ("The value of 'a & b' is " + (a & b));
Console.WriteLine ("The value of 'a | b' is " + (a | b));
/*
The results for the above program will be:
Output:
The value of 'a' is 10
The value of 'b' is 20
The value of 'a & b' is 0
The value of 'a | b' is 30
*/
Logical operators (&&, ||) USUALLY (but not always) are used whenever a conditional value needs to be found out.
Whereas, Bitwise operators (&, | and ^) USUALLY(but not always) are used whenever a bitwise ANDing or ORing or XORing needs to be done. These 3 operators are mainly used in systems programming.
Regards
Vinay V
It is better to fail when you tried than to fail to try.
JackWilliams
Member
31 Points
24 Posts
difference between & and && operator in c#
Aug 07, 2009 01:34 PM|LINK
Hi
I am little bit confusing about where and what scenario the & and && operator used.
I would like to know the difference between & and && in c# with an example. I refered some of websites but it is confusing
-Thanx
krunal.shah
Participant
1434 Points
224 Posts
Re: difference between & and && operator in c#
Aug 07, 2009 02:02 PM|LINK
Hi,
'&&' and '||' are what's called "short-circuiting" logical operators.
In the case of &&, if the first operand is false, then it doesn't bother evaluating the second operand, because the whole expression is certain to be false.
In the case of ||, if the first operand is true, then it doesn't bother evaluating the second operand, because the whole expression is certain to be true.
'&' and '|' can also be used as logical operators though it's more common for them to be used as bitwise operators. When they're used as logical operators, both operands are always evaluated.
Krunal
Please Mark as answer if it helps.it will help others to find the solution.
Zeeshan A. S...
Member
6 Points
6 Posts
Re: difference between & and && operator in c#
Aug 07, 2009 02:14 PM|LINK
&& is used in conditional statements. i.e.,if we write:
if(firstName == 'John' && lastName == 'Bell')
{
Response.Write("Welcome John Bell!");
}
the Response.Write statement will run only if both variables firstName and lastName match to their condition.
Whereas & operator is used for Binary AND operations, i.e., if we write:
bool a, b, c;
a = true;
b = false;
c = a & b;
Response.Write(c); // 'False' will be written to the web page
Here first Binary And operation will be performed on variables a and b, and the resultant value will be stored in variable c.
Sr. Software Engineer
e-Bizsoft Private Limited
Karachi, Pakistan
+923452826119
ErnestoWww
Member
42 Points
8 Posts
Re: difference between & and && operator in c#
Aug 07, 2009 02:29 PM|LINK
The && is the Conditional AND Operator and is used to evalute if multiple statements are true using the if statement (or false depending on what you're testing for)
int x = 3;
int y = 7;
if( (x==3) && (y==7))
{
//some command here
}
This statement would evaluate to True since x really does equal 3 and y really does equal 7. (because we set them to those values).
The & is the Logical AND Operator and as far as I can tell operates the same as the above, though this one appears to take a higher priority.
Hope that helps, I referenced O'Reilly Learning C# 2005 pg. 66-68 and this link http://visualcplus.blogspot.com/2006/02/lesson-8-conditional-and-logical.html
Remeber to Mark As Answer if this is the solution you were looking for.
Thanks
sharmoon
Member
355 Points
65 Posts
Re: difference between & and && operator in c#
Aug 08, 2009 10:45 AM|LINK
Hi JackWilliams, Please visit the following link to know detains about {AndAlso (&&) and And (&)}:
http://www.c-sharpcorner.com/UploadFile/jaishmathews/AndAlsoOrElseOperatorsinCSharp03112006104809AM/AndAlsoOrElseOperatorsinCSharp.aspx
Don't forget to click on "Mark as Answer" if I trust you.
Thank you...
vinay.v.rama...
Member
192 Points
58 Posts
Re: difference between & and && operator in c#
Aug 08, 2009 07:49 PM|LINK
&& (double ampersand), || (double pipe), & (single ampersand), | (single pipe) and ^ (carat symbol) all operate on the same principal. i.e. use truth table for the execution. See below for the truth table.
&& (double ampersand) and || (double pipe) are conditional operators. These two operators are used to compare two results' boolean value and hence decide on the next course of action.
bool firstCondition = true; bool secondCondition = true; // The code block following the if condition is executed only if firstCondition and // secondCondition both are true. Otherwise, the if block is skipped. if(firstCondition && secondCondition) { //Do Something; } // The code block following the if condition is executed if either the right hand operand // or left hand operand is true. if(firstCondition || secondCondition) { //Do Something; }Remember the following truth table.
T -> Truth
F -> False
AND can be either && or &
and OR can be either || or |
Truth Tables
X AND Y -> Result
---------------------
T AND T -> T
T AND F -> F
F AND T -> F
F AND F -> F
X OR Y -> Result
---------------------
T OR T -> T
T OR F -> T
F OR T -> T
F OR F -> F
As you see from the result, && results to false when either of the operand is false, whereas || results to truth when either of the operands is true.
& (single ampersand), | (single pipe) and ^ (Used for XOR in C#) are called as bitwise operators. Because they operate on bits instead of on conditions.
For eg. if X = 4 and Y =3
The resultant value for
X & Y = 4 & 3 = 0
X | Y = 4 | 3 = 7
This is because, the bitwise operators work on bits instead of on conditions...
So 4 in binary is 0100 and 3 in binary is 0011 - and remember from the truth table "and" operator results into "true" only when both the operands are true otherwise false. So
0 1 0 0
& 0 0 1 1
---------
0 0 0 0 -> because 0 => false and 1 => true
0 1 0 0
| 0 0 1 1
-----------
0 1 1 1 -> and when we convert 0111 from binary to decimal we get 7.
int a = 10; int b = 20; int c = a & b; Console.WriteLine ("The value of 'a' is " + a); Console.WriteLine ("The value of 'b' is " + b); Console.WriteLine ("The value of 'a & b' is " + (a & b)); Console.WriteLine ("The value of 'a | b' is " + (a | b)); /* The results for the above program will be: Output: The value of 'a' is 10 The value of 'b' is 20 The value of 'a & b' is 0 The value of 'a | b' is 30 */------------------------------------------------------------------------------------------------------------------
Logical operators (&&, ||) USUALLY (but not always) are used whenever a conditional value needs to be found out.
Whereas, Bitwise operators (&, | and ^) USUALLY(but not always) are used whenever a bitwise ANDing or ORing or XORing needs to be done. These 3 operators are mainly used in systems programming.
Vinay V
It is better to fail when you tried than to fail to try.
velpuri
Member
36 Points
14 Posts
Re: difference between & and && operator in c#
Aug 11, 2009 12:29 PM|LINK
HI,
Please have a look at the following link:
http://jeremyjarrell.com/archive/2007/03/08/14.aspx
Many Thanks,
Hari.