C# Operators

One of the first programming surprises I can remember is when I wrote this line of code in C++ many years ago…

if ( speedSetPoint = 10000) maxSpeedSet = true;

Now the intention was to run the machine at a slow 5% speed or “speedSetPoint =500” since this was a new machine installation and startup. However, that was not what happened, the speed shot past 5% and went to 100%. It was very fortunate that the rotation of the drive motor was correct or mechanical damage could have resulted.

So what happened? By using the C++ Assignment Operator “=” instead of using the Comparison Operator “==” I assigned the value of 10,000 or 100% speed to “speedSetPoint”. Using a “=” sign in an “IF’ statement will not cause a compiler error in C++ or C#. You would think by now using a “=” in an “if” statement would generate a warning, and in some compilers, it may do just that but not MS C# studio. So we have to be careful, especially during our late-night indie development sessions.

So what is the difference between Assignment and Comparison Operators? Both are used as a type of shorthand. Assignment Operators assign a value to a variable. And Comparision Operators compare the values of two variables and return a “true” or “false”.

Here are some Assignment Operator examples we use in Unity game development.

“=” this simply assigns a value to a variable X=10;

“+=” Ex… X+=5; is the same as X= X+5; which adds 5 to X and assigns the result to X.

“-=” Ex… X-=5; is the same as X=X-5; which subtracts 5 from X and assigns the result to X.

“*=” Ex…X*=4; is the same as X=X*4; which multiplies X by 4 and assigns the result to X.

“/=” Ex… X/=2; is the same as X=X/2; which divides X by 2 and assigns the result to X.

“%=” Ex… X%=2; is the same as X%=2; which divides X by 2, but assigns the value of the division remainder to X.

Here are some Comparison Operator examples we use in Unity game development.

“==” Ex… if(X==100) If X is equal to 100,the statement is true.

“!=” Ex… if(X!=100) If X is equal to 100, the statement is true.

“>” Ex… if(X>Y) If X is greater than Y, the statement is true.

“<” Ex… if(X<Y) If X is less than Y, the statement is true.

“> =” Ex… while(X> =Y) If X is greater than or equal to Y, the statement is true.

“< =” Ex… while(X< =Y) If X is less than or equal to Y, the statement is true.

This is not a complete list of all of the C# operators for the complete list check out the Microsoft C# Documentation on C# Operators and Expressions here https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/

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