One of the single most important statements in every programming language is the if statement. Being able to set up conditional blocks of code is a fundamental principal of writing software. If you have already used another programming language, chances are that you can use the if statement in C# straight away.
The if statement needs a boolean result, that is, true or false. In some programming languages, several datatypes can be automatically converted into booleans, but in C#, you have to specifically make the result boolean. For instance, you can't use if, but you can compare a number to something, to generate a true or false, like we do later on. The conditional if statement accepts a boolean expression or a condition inside brackets or as a parameter which is followed by a single line or multi-line block of code. During the runtime, when the program has been executed, the condition inside the brackets is evaluated. If this boolean expression results in true, then the code block following the if statement will be executed.
The if statement is also known as a decision making statement, as it makes a decision on the basis of a given condition or expression. The block of code inside the if statement is executed is the condition evaluates to true. However, the code inside the curly braces is skipped if the condition evaluates to false, and the code after the if statement is executed. Conditional statements are a part of every programming language.
You will find them in every application with a significant amount of code. Because they are part of the basic fundamentals of coding, you need to know the C# if else structure. (New to C#? Learn the basics.) The basic if statement is a part of any C-derived language, and you can use it to control the execution of code. The most difficult part of learning conditional statements is understanding the logic behind it. When you understand the logic, you know which part of the if else statement will execute. Similar to all other programming languages, in C# also the "if-else statement" is used for checking whether a condition is true or not.
Evaluate multiple conditions in a row with C#'s cascaded if statementC#'s cascaded if statement evaluates a series of true/false expressions. A cascaded if statement needs two features before we can replace it with conditional operators. First, there should only be one statement in the if, else if, and else code blocks. Second, the value that the conditional operators are going to return needs to be used in the same statement . There has to be a single statement in the if, else if, and else blocks.
When there are several lines of code there, then we cannot replace the cascaded if statement with conditional operators. That's okay because true and false aren't being used like in the first example. In C, like in other programming languages, you can use statements that evaluate to true or false rather than using the boolean values true or false directly.
Another type of cascaded if statement is one that executes a method conditionally. When we use that method's returned value in the same statement, we can replace those ifs with conditional operators. In early programming languages, especially some dialects of BASIC in the 1980s home computers, an if–then statement could only contain GOTO statements . This led to a hard-to-read style of programming known as spaghetti programming, with programs in this style called spaghetti code.
In this example, the else statement is executed if the testing variable does not contain the "testing" string. You could add even another embedded if statement and continue with embedded if statements. However, it's generally considered bad coding practice to have too many embedded if statements. It's considered bad coding practice to have several if statements with more embedded statements, because it's difficult to read for other coders.
In the above code, if myCondition is false, the condition's value is printed. However, if myCondition is true, the second statement "The else statement was executed" is printed. Additionally, if you remove the exclamation mark, the logic is switched and the else statement is always executed. But while similar to if/else, the conditional operator is much shorter to write.
It's also more flexible and can, for example, be used as an inline expression. Let's see how it compares with if/else statements. After that we'll see how multiple conditional operators can replace a cascaded if statement.
In the same way, we can use if statements to tell our program to perform certain functions based on a variety of conditions. We can expand the statement to tell our program to run a certain block of code if the condition is true, but run a different block of code if the condition is false. We will do this by using an if-else conditional statement.
Following is the example of defining theif-else-if statement in c# programming language to execute the block of code or statements based on a Boolean expression. In computer science, conditionals are programming language commands for handling decisions. Specifically, conditionals perform different computations or actions depending on whether a programmer-defined boolean condition evaluates to true or false. In terms of control flow, the decision is always achieved by selectively altering the control flow based on some condition .
Each C# variable has a default value (even when we don't explicitly set it). And so we can always use this approach to set a variable's value with a series of conditional operators – even when the original cascaded if statement had no default else block. Let's look at an example of the three kinds of cascaded if statements we can replace with conditional operators. After that we'll look at the cascaded ifs we cannot replace. Here, condition is some Boolean expression that evaluates to either true or false, and the statements inside the code block should be executed if a condition is true.
The if-else-if ladder statement executes one condition from multiple statements. The execution starts from top and checked for each if condition. The statement of if block will be executed which evaluates to be true. If none of the if condition evaluates to be true then the last else block is evaluated. In Visual Basic and some other languages, a function called IIf is provided, which can be used as a conditional expression.
If the condition returns the boolean "true," then the coded statements within the if statement are executed. You can add several conditional statements in one if statement, but it makes it more difficult to keep track of the logic. This is not necessarily a bad thing, but it might not be what you want — often you want to run one block of code or the other, not both. In any programming language, the code needs to make decisions and carry out actions accordingly depending on different inputs. For example, in a game, if the player's number of lives is 0, then it's game over. In a weather app, if it is being looked at in the morning, show a sunrise graphic; show stars and a moon if it is nighttime.
In this article, we'll explore how so-called conditional statements work in JavaScript. As observed, the else statement does not contain any boolean expression. The block of code following the else statement is always executed whenever the condition is given in the 'if' brackets evaluates to be false. The "if" condition or the if-else condition takes up a boolean expression as its parameter and evaluates it. Only if the condition being evaluated is true, the block of a statement under if the statement is executed. In case the condition is false, the if block will be skipped.
The if/else if statement allows you to create a chain of if statements. The if statements are evaluated in order until one of the if expressions is true or the end of the if/else if chain is reached. If the end of the if/else if chain is reached without a true expression, no code blocks are executed. Case statements are used to set different conditions. Based on the conditions, a set of statements can be executed. A switch statement can have multiple case conditions.
The first case statement checks to see if the value of the variable is equal to 1. But that third and last value can also be another conditional operator. That makes it possible to check another true/false expression. When we use conditional operators like that, we string multiple together and evaluate a range of situations. When we have additional conditions to evaluate, we can use the else if statement, as shown on Lines 18 and 23. If the evaluation in Line 13 is true, the additional checks will not run.
If the condition is not true, our program will continue to Line 18 and evaluate that statement. Similarly, if the condition in Line 18 is true, the code block between Lines 19 and 22 will run and any future conditions in the if... Construct will not be evaluated; if the condition is false, it will skip the code block and evaluate the next condition . If the expression within the parentheses of our if statement evaluates to true, then our program will execute the code inside the code block between lines 14 and 17. If the expression is not true, the statements inside the code block will be ignored and our program will continue with the statement on line 19.
Generally, in c# if statement or if-else statement is useful when we have one condition to validate and execute the required block of statements. If we have multiple conditions to validate and execute only one block of code, then theif-else-if statement is useful in our application. The C# if else statement is one of the most commonly used control flow statement. With if statements, you can tell the computer to make a choice by evaluating a Boolean logical expression called condition. It allows you to tell the computer whether to run the code inside the block based on the condition or set of conditions.
Each Boolean expression can be independent of the others and can include any of the comparison and logical operators. The if statement contains a boolean condition followed by a single or multi-line code block to be executed. At runtime, if a boolean condition evaluates to true, then the code block will be executed, otherwise not.
A programming language uses control statements to control the flow of execution of program based on certain conditions. These are used to cause the flow of execution to advance and branch based on changes to the state of a program. If the condition for the if statement evaluates to false, the condition for the else...if statement is checked. If that condition evaluates to true, the code inside the else...if statement's curly braces is run. In this tutorial we learn how to conditionally control the flow of our application with if, else, else/if and switch statements. Proper indenting makes it easier to see the matching.
Just remember that in an if or else statement, if the expression is true, the program executes the following curly bracketed code block or single statement. The if… else construct is used for determining the flow of program based on returning expression value. It evaluates the comparison operator and based on value executes the statements. For example, if you want to execute a piece of code when the requirements meet then if… else construct determine which piece of code will be executed.
Else is default condition and executes when no if condition matches. The following example will clear the concept of if… else constructs. In any event, keep in mind that we are ultimately testing for conditions that can be either true or false.
Such conditions may come in the form of a single boolean variable or a more complex expression involving relational or logical operators. So this is how we check the conditions under if , else if and if blocks respectively . And the conditional operators need to return a value that's used in the same line of code.
We might for instance use that value to set a method argument or update a variable. With C#'s if/else statements we evaluate a condition and, when true, execute the code directly below the if keyword. For a false condition, our app runs the code below else. A cascaded if statement expands on this behaviour, and evaluates a series of conditions and then executes code for the one that's true. Second, we have declared and assigned our message variable in each code block of our if statements.
It would be better practice to declare the string variable once before testing all the conditions, and then simply assign a value to the variable depending on the user's input. This is how we can use theif-else-if statement in the c# programming language to execute the block of code or statements based on our requirements. If the boolean expression evaluates to true, then the if block of code is executed, otherwise else block of code is executed.
The if statement is used to conditionally execute a statement or a block of statements. Conditions can be true or false, execute one thing when the condition is true, something else when the condition is false. Several decision-making statements are available in C# where certain logical conditions are required to flow a program continuously. The decision-making statements included in C# are – if statement, if-else statement, switch statement, and ternary operator.
Flow control and conditional statements are available in any programming language to alter the flow of a program. If statement in C# is used to evaluate a set of statements conditionally based on an expression that evaluates to true or false. When true, the if/else statement and conditional operator execute expression1. And when the condition is false, the code runs expression2.
When that expression is true, the operator executes its second value. And when that true/false expression is false, the conditional operator runs the third and last value (Asad & Ali, 2017; Stephens, 2014). This has the conditional operator always either execute its second or third expression. If no conditions are matching, the else block will be executed.
