In Rust, if. Else .if statement allows us to add alternative set of test conditions in if. Else statement using else -if and single else statements for if condition. In such way if. Else .if statement is used to select one among several blocks of code to be executed.
Here's a table of contents of what you'll learn in this lesson:(click on a link to skip to its section) Rust allows us to control the flow of our program through specific expressions that evaluate conditions.
Based on the result of these conditions, Rust will execute sections of specified code. Before a user can gain access to the member area, they need to provide the correct login credentials.
If they provide the correct credentials, they are allowed into the exclusive member area. Our actual code will not look exactly like the example above, but it serves to give you an example of what conditional control is.
We control the flow of our program with the following statements, in combination with relational comparison and logical operators. If the condition proves true, the compiler will execute the if statement’s code block.
An if statement is written with the keyword if, followed by the condition(s) we want it to evaluate. Then, we specify a code block with open and close curly braces.
Inside the code block we write one or more expressions to be executed if the evaluation proves true. The closing curly brace will tell the compiler where the if statement ends.
The compiler then prints the message inside the if statement’s code block. When the compiler has finished executing the if statement, it will move on to any code after it.
In the example above, the first condition proves false, but the second condition proves true so the compiler is allowed to execute the code in the code block. The compiler will move to evaluate each if statement in the ladder when it’s done with previous one.
In the example above, we add a secondary if statement at the end of the first, separated by the else keyword. The compiler will perform the evaluations hierarchically, that’s to say, it will start out the outer if statement and move inwards.
The compiler then evaluates the inner if statement and executes its code block if its condition proves true. If you’re familiar with a languages in the C family, it would be similar to a switch statement, although the syntax is different.
Note that the code block is terminated with a semicolon after the closing curly brace. The final value to match is simply an underscore.
In this case, it matched to “B” on the left and so it printed the string “Great job, you got a B!”. This is simply because we don’t need to, the execution statement of the match already prints a message.
When the compiler finds a match on the left of the operator, it will return the value on the right of the into the result variable. This time, the compiler matched to “A” on the left, so it stored the string “Excellent!” into the result variable.
To do this, we simply write the if statement where the value should be in the variable initialization. The execution expressions must provide a value to be assigned to the variable.
The individual statements in the code blocks are not terminated with a semicolon. The if statement itself is terminated with a semicolon after the else closing curly brace.
In the example above, the if statement will prove true so the value assigned to the number variable is 1. If we try to assign different types of values to it through the if statement, the compiler will raise an error.
In many languages, such as C or Python we can write a shortened version of a simple if/ else statement, known as the ternary operator. Rust, removed the ternary operator back in 2012.
We can conditionally set the value of a variable with an if statement with an if let expression. An if let expression places the if statement as the value of a variable declaration.
An if let expression is terminated with a semicolon after the code block closing brace. Values inside the code blocks of an if let expression are not terminated with a semicolon.
Therefore, condition given in 'if' is true and the string passed as a parameter to the print! If the condition is true then 'if' block is executed and the statements inside the else block are skipped.
If the condition is false then else block is executed and the statements inside the 'if' block are skipped. Therefore, else block is executed and prints “an is smaller than b” on the screen.
When you want to check the multiple conditions, then else -if' statement is used. In the above syntax, Rust executes the block for the first true condition and once it finds the first true condition then it will not execute the rest of the blocks.
When an if- else statement is present inside the body of another if or else block then it is known as nested if- else. So, control goes inside the 'if' block and the value of an is less than b.
Vials of touch-up paint and clear coat, but call the parts department first to see if your color is in stock. Most auto parts sites explain how to find the paint code for your vehicle.
At an auto parts store, pick up a can of wax and grease remover, and if you already have rust forming, an assortment of sandpaper grits and a bottle of brush-on rust converter. Photo: Shutterstock Spot-sanding tool Foam brush Professional micro applicators Paint syringes 1/4-in.
Vials of touch-up paint and clear coat Wax and grease remover Assortment of sandpaper grits Bottle of brush-on rust converter Photo: Shutterstock Before touching up the paint on your car, wash your vehicle.
Let it dry and apply the wax and grease remover with a clean rag to the areas you’re touching up. Also use the spot-sanding tool to remove rust from scratches and larger paint chips.
Photo: Shutterstock Then follow the instructions on the bottle of rust converter and use a foam brush to apply a thin coating to the area. If you don’t have any rust and the factory primer is visible, you can skip those steps and proceed with painting.
For dents, use the artist’s brush to apply a light coat of paint to the treated area. Thick blobs skin over and then sink as they dry, leaving an ugly divot.
To repair scratches, apply the brush head to the syringe and load it with a small amount of paint. Then apply light pressure to the plunger as you guide the brush head all along the scratch.