switch vs if else

 

if-else vs switch

What is an if-else statement?

An if-else statement in C programming is a conditional statement that executes a different set of statements based on the condition that is true or false. The 'if' block will be executed only when the specified condition is true, and if the specified condition is false, then the else block will be executed.

1. if-else Statements:

   The if-else statement is used to execute a block of code based on a condition. It evaluates a Boolean expression, and if the expression is true, the code inside the if block is executed; otherwise, the code inside the else block is executed (if present).
   
   You can also have multiple else if clauses to test multiple conditions in sequence.

   The syntax is as follows:

   • c
     if (condition1) {
         // code to execute if condition1 is true
     } else if (condition2) {
         // code to execute if condition2 is true
     } else {
         // code to execute if no conditions are true
     }

   • if-else statements are flexible and can handle complex conditions.

     What is a switch statement?

     A switch statement is a conditional statement used in C programming to check the value of a variable and compare it with all the cases. If the value is matched with any case, then its corresponding statements will be executed. Each case has some name or number known as the identifier. The value entered by the user will be compared with all the cases until the case is found. If the value entered by the user is not matched with any case, then the default statement will be executed.

     2. switch Statement:

     The switch statement is used when you want to compare a single value against multiple possible constant values. It provides a way to streamline code that would otherwise involve multiple if-else statements.

     The switch statement takes an expression and compares it against different cases. If a match is found, the code within that case block is executed.

     It is important to note that the expression within the switch must result in an integral value (e.g., int, char) or an enumeration constant.

     The syntax is as follows:

     • c
       switch (expression) {
           case value1:
               // code to execute if expression equals value1
               break; // optional, used to exit the switch block
           case value2:
               // code to execute if expression equals value2
               break;
           // more cases
           default:
               // code to execute if no cases match expression
       }

       Differences b/w if-else and switch statement

       1. Usage:

          if-else: It is used when you have complex conditions or need to evaluate expressions that result in a Boolean value (true or false). It allows you to handle a wide range of conditions.

          switch: It is used when you want to compare a single value against multiple possible constant values. It is particularly useful when you have a series of conditions based on the same variable or expression.

       2. Expression Type:

          if-else: The condition in an if-else statement is an expression that results in a Boolean value (true or false).

          switch: The expression in a switch statement must evaluate to an integral value (e.g., int, char, or enumeration constant).

       3. Conditions:

          if-else: You can have complex conditions involving relational operators (>, <, >=, <=), logical operators (&&, ||, !), and parentheses. You can also have multiple else if clauses to test multiple conditions in sequence.

          switch: It allows you to test the equality of a single expression against multiple constant values using case labels.
          
          
          

       4. Execution Flow:

          if-else: The if-else statement evaluates conditions sequentially, and once a true condition is found, the corresponding block of code is executed, and the control exits the if-else structure.

          switch: The switch statement compares the expression against case labels. Once a matching case is found, the code within that case block is executed. If a break statement is not used, execution continues to subsequent cases until a break or the end of the switch block is encountered.

       5. Default Case:

          if-else: There is no direct equivalent to a default case in an if-else structure. You can use an else block to handle cases that do not match any of the specified conditions.

          switch: You can include a default case in a switch statement to handle cases where none of the specified case labels match the expression.

       6. Fall-Through:

          if-else: There is no concept of fall-through in an if-else structure. Once a condition is met and its code block is executed, the control exits the structure.

          switch: In a switch statement, if you don't use a break statement after a case block, execution will "fall through" to subsequent cases until a break or the end of the switch block is encountered. This can be used intentionally for some specific scenarios.

          Let's summarize the above differences in a tabular form

          • 	If-else	switch
            Definition	Depending on the condition in the 'if' statement, 'if' and 'else' blocks are executed.	The user will decide which statement is to be executed.
            Expression	It contains either logical or equality expression.	It contains a single expression which can be either a character or integer variable.
            Evaluation	It evaluates all types of data, such as integer, floating-point, character or Boolean.	It evaluates either an integer, or character.
            Sequence of execution	First, the condition is checked. If the condition is true then 'if' block is executed otherwise 'else' block	It executes one case after another till the break keyword is not found, or the default statement is executed.
            Default execution	If the condition is not true, then by default, else block will be executed.	If the value does not match with any case, then by default, default statement is executed.
            Editing	Editing is not easy in the 'if-else' statement.	Cases in a switch statement are easy to maintain and modify. Therefore, we can say that the removal or editing of any case will not interrupt the execution of other cases.
            Speed	If there are multiple choices implemented through 'if-else', then the speed of the execution will be slow.	If we have multiple choices then the switch statement is the best option as the speed of the execution will be much higher than 'if-else'.