C#•4mo ago

✅ Hello, could you help me understand `&`, `&&`, `|`, `||` in C# with this code example:

int a = 4, b = 3, c = 2, d = 1;

if (a / b > 1 & c - d < 1 | a % 2 == 0)
    label1.Text = "everything's cool";
else
    label1.Text = "everything's bad";

int a = 4, b = 3, c = 2, d = 1;

if (a / b > 1 & c - d < 1 | a % 2 == 0)
    label1.Text = "everything's cool";
else
    label1.Text = "everything's bad";

Why does the if condition execute when a/b>1 is false? The ampersand & upon encountering the first false, immediately triggers else, and evaluates the rest of the expression in the background (right??). Its further calculation of other expressions after the & should not change the outcome (?), as it is not the OR operator |. Why do we then end up with 'everything's cool'?"

14 Replies

mtreit•4mo ago

& is not short-circuiting. && is I'm not sure what you are asking actually, what do you mean by "evaluate the rest of the expression in the background" ?

flask•4mo ago

According to the information I have, & is an ampersand "and", returns false the first time False is triggered, but also counts the remaining expression in memory (not sure what are the use cases for it, maybe I'm wrong about it in the first place). The double ampersand && does not read the rest of the expression the first time False (so a/b>1 gives False, the rest doesn't matter since it's already else), thus working faster.

mtreit•4mo ago

You normally do not want to use non-short-circuiting operators for logical operations.

returns false the first time False is triggered, but also counts the remaining expression in memory

Whatever this is trying to say is not right. The entire expression gets evaluated if you use & and | before producing a final result that is either true or false You also need to be careful to parenthesize your conditions to ensure it's doing what you think. false & true | true evaluates to true false & (true | true) evaluates to false

oke•4mo ago

& and | are called bitwise operators. They are used for manipulating binary numbers. && and || are boolean operators.

mtreit•4mo ago

Well, they can also be used as logical operators. As is the case here. But yes normally you never use these except for bitwise operations.

oke•4mo ago

for simplicity's sake, i narrowed it down probably stole your thunder a little bit by saying it right after your novel 😬

mtreit•4mo ago

Nah it's fine 🙂

oke•4mo ago

read this for more on binary operators: https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/operators/bitwise-and-shift-operators read this for boolean operators: https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/operators/boolean-logical-operators

Bitwise and shift operators - perform boolean (AND, NOT, OR, XOR) a...

Learn about C# operators that perform bitwise logical (AND - &, NOT - ~, OR - |, XOR - ^) or shift operations( <<, and >>) with operands of integral types.

Boolean logical operators - the boolean and, or, not, and xor opera...

C# logical operators perform logical negation (!), conjunction (AND - &, &&), and inclusive and exclusive disjunction (OR - |, ||, ^) operations with Boolean operands.

mtreit•4mo ago

So false & true | true evaluates to true whereasfalse && true | true and false && true || true both evaluate to false

oke•4mo ago

this whole thing is just a cluster fuck of c#

Moods•4mo ago

Please use your brackets though...to avoid ambiguities

flask•4mo ago

Thank you so much for your help 👍

Denis•3mo ago

$close

MODiX•3mo ago

Use the /close command to mark a forum thread as answered

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✅ **Hello, could you help me understand `&`, `&&`, `|`, `||` in C# with this code example:**

✅ Hello, could you help me understand `&`, `&&`, `|`, `||` in C# with this code example: