L-11 = What is Coding & C Programming Language

Why do we need a Switch case?

There is one problem with the if statement: the program's complexity increases whenever the number of if statements increases. If we use multiple if-else statements in the program, the code might become difficult to read and comprehend. Sometimes it also even confuses the developer whom himself wrote the program. Using the switch statement is the solution of this problem.

syntax

                    

                        int a = 2;
                        switch (a)
                        {
                        case 2:
                            break;
                            // after checking case 2 it won't go to case 3 instead it will exit and it will not print the default case.
                            printf("value is 2");
                        case 3:
                            printf("value is 3");
                        default:
                            printf("nothing matched");
                        }

Rules for Switch Statement

The test expression of Switch must be an int or char.
The value of the case should be an integer or character
Case must come inside swtich
Break is not necessary
The case label values inside the switch should be unique.
int x; ✓ float x; ✗

Difference between a switch and if:

Switch statements cannot evaluate float conditions, and the test expression can be an integer or a character, whereas if statements can evaluate float conditions.
The switch statement cannot evaluate relational operators i.e., they are not allowed in switch statements, whereas if statements can evaluate relational operators.
Cases in the switch can never have variable expressions; for example, we cannot write case a +3 :

Example Code

Simple Switch

                            
                                
                                #include <stdio.h>
                                
                                int main()
                                {
                                    int i = 9;
                                    
                                    switch (i)
                                    {
                                    case 5:
                                    printf("Value is 7");
                                    break;
                                    
                                    case 0:
                                    printf("Value is 8");
                                    break;
                                    
                                    case 9:
                                    printf("Value is 9");
                                    break;
                                    
                                    default:
                                    printf("Value is not present");
                                    break;
                                }
                                return 0;
                            }

Nested Switch

                        

                            switch (expression 1)
                            {
                                Case 1 : printf(“Switch Statement 1”);
                            
                                switch (expression 2)
                                {
                                    Case 1 : printf(“Switch Statement 2”);
                                    Break;
                            
                                    Case 2 : Do this;
                                }
                                break;
                                Case 2 : Do this;
                            }

C Programming