Learn How To Program In C# Part 2 – Expressions And Operators


Hey, everyone. Today we will be going over expressions and
operators. First and foremost, let’s define these terms. An expression is a series of operators and
operands. What are operators and operands? Operators are basically symbols that represent
an operation which returns a single result. So plus, minus, division, multiplication,
assignment, equality checks, all those are examples of operators. And operands are the inputs for your operators. Operands are data elements that are used as
inputs for operators. 5-10 is an expression, and it’s made out
of operators and operands. 5 and 10 would be the operands and ‘-‘ would
be the operator. So 5 and 10 are the operands that are inputs
for your ‘-‘operator in order for the operation to happen. And once the operation happens, you will get
a single result. One more thing is that expressions can be
combined into more complex expressions. The way you combine expressions is through
operators. You might be asking how do we get a result
back. That happens through evaluation. Your expressions will be evaluated down to
a single result. Evaluation is pretty much the process of applying
operators to operands in the proper sequence. The key is proper sequence. In this video, I will not be going over the
way the proper sequence works, but it’s good to keep in mind that there is a proper
sequence when your expression gets evaluated down to a single result. In the future videos, I will be showing you
the actual sequence. But for the sake of simplicity, I just want
to show you how expressions work and how you can combine expressions together, and when
you get value, what to do with it, and how you can assign that value to a variable, which
we already went over, what variables are, how to use them, why they exist. I want to show you all that so you can combine
these two new concepts together. And later down the line, we will definitely
go over the sequence and how your expressions get evaluated. Without further ado, let’s go ahead and
create a new project. Let’s call it ExpressionsAndOperators. You already know the Solution Explorer. I went over the solutions, projects, and what
they mean. This is the Main method. This is where the execution of our program
begins. Let’s create a variable called simpleExpression1. int simpleExpresssion1=5 – 10;
Here, 5 and 10 are the operands for the operator ‘-‘. And then this gets evaluated down
to result. Once that happens, you then assign the result
of that to simpleExpression1 variable. How does that happen? ‘=’ is called the
assignment operator. This assignment operator takes in two operands. What are those two operands? The operand on the left is the variable declaration. We already went over that, the type, the variable
name. It takes the left side and it takes the right
side. These are the inputs for the assignment operator. And what the assignment operator does when
it gets evaluated is it assigns the value from the right side to its left side. That’s what happens. You have your operator1 (-) and your operator2
(=) here. Now we can go ahead and create another expression:
int simpleExpression2=4 * 10; And pretty much the same thing will happen. Let’s create another variable. int complexExpression=(((6*7) – 4) + simpleExpression1)
/ simpleExpression2; The numbers don’t matter. None of this matters. It’s just that I want you to understand
how the evaluation process works and how you can use the variables in this scenario and
how you can use other variables in a complex expression. As to what these numbers mean, they mean nothing. In this case, there’s no special meaning. There’s not a formula. So don’t pay attention to that. This is just for the sake of the example. The above statement looks a bit more complex. This
right here shows you that you can get the value in a variable using the assignment operator. And you have you expression here. You put those in a variable. And you can use those variables in another
expression. And you can use this variable in another expression. You can see that this is pretty powerful. Let’s print out this variable. Console.WriteLine(simpleExpression1);
Console.WriteLine(simpleExpression2); Console.WriteLine(complexExpression); And we can run the program. Let’s put the break point right here and
run the program. Following is the output:
-5 40
0 The value returned from simpleExpression1
is -5, simpleExpression2 is 40, and complexExpression is 0. The reason why this is 0 is that we have our
type as int. We can actually change that to decimal. Let’s do that. decimal simpleExpresssion1=5 – 10;
decimal simpleExpression2=4 * 10; decimal complexExpression=(((6*7) – 4) +
simpleExpression1) / simpleExpression2; Console.WriteLine(simpleExpression1);
Console.WriteLine(simpleExpression2); Console.WriteLine(complexExpression);
We now should get result back. Let’s run this. -5
40 0.825
complexExpression is 0.825. Those are not related to the expressions and
operators, but just wanted to show you that that was the reason why we got a 0 back as
a result. That’s it. These are the basics of expressions and operators. And later down the line, we’ll go over the
proper sequence in which they get evaluated. But for now, that’s it. I hope you enjoyed the video. And please, don’t forget to subscribe.

7 Replies to “Learn How To Program In C# Part 2 – Expressions And Operators”

  1. int complexExpression = (6 * 7) – 4) + simpleExpression1) / simpleExpression2;

    why would my "4)" become an error?

  2. I didt really understand what changing your integer to a decimal did. Why did it return 0 when it was an integer? What does a decimal variable do?

  3. man! i searched for many many tutorials to teach me how to program, but none of them were good, until i find you….your tutorials…are the best!

  4. Your videos are great! It took me a long time to find them too! I need more help with this so keep posting. Thanks!

  5. why didn't you change your mvs settings to auto add the spaces within your operations. I'm back here to revise my c# after a few years away and this seems so inefficient

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