Switch Statement
#The switch statement in C language is used to execute the code from multiple conditions or case. It is same like if else-if ladder statement.
A switch statement work with byte, short, char and int primitive data type, it also works with enumerated types and string.
Syntax
switch(expression or variable) { case value: //statements // any number of case statements break; //optional default: //optional //statements }
Flow chart
Rules for apply switch
- The switch expression must be of integer or character type.
- With switch statement use only byte, short, int, char data type.
- With switch statement not use float data type.
- You can use any number of case statements within a switch.
- The case value can be used only inside the switch statement.
- Value for a case must be same as the variable in switch.
Valid statement for switch
Example
int x; byte y; short z; char a,b;
Limitations of switch
Logical operators can not be used with switch statement. For instance
Example
case k>20&&k=20: // is not allowed
Switch case variables can have only int and char data type. So float data type is not allowed.
case 4.2: // Invalid
Syntax
switch(ch) { case 1: statement 1; break; case 2: statement 2; break; }
In this ch can be integer or char and can not be float or any other data type.
Rulse table of switch
| Valid Switch | Invalid Switch | Valid Case | Invalid Case |
|---|---|---|---|
| switch(a) | switch(2.3) | case 3; | case 2.5; |
| switch(a>b) | switch(a+2.5) | case 'a'; | case x; |
| switch(a+b-2) | case 1+2; | case x+2; | |
| switch(func(a,b)) | case 'a'>'b'; | case 1,2,3; |
Example of switch case
#include<stdio.h> #include<conio.h> void main() { int ch; clrscr(); printf("Enter any number (1 to 7)"); scanf("%d",&ch); switch(ch) { case 1: printf("Today is Monday"); break; case 2: printf("Today is Tuesday"); break; case 3: printf("Today is Wednesday"); break; case 4: printf("Today is Thursday"); break; case 5: printf("Today is Friday"); break; case 6: printf("Today is Saturday"); break; case 7: printf("Today is Sunday"); break; default: printf("Only enter value 1 to 7"); } getch(); }
Output
Enter any number (1 to 7): 5 Today is Friday
Note: In switch statement default is optional but when we use this in switch default is executed at last whenever all cases are not satisfied the condition.
Example of Switch without break
#include<stdio.h> #include<conio.h> void main() { int ch; clrscr(); printf("Enter any number (1 to 7)"); scanf("%d",&ch); switch(ch) { case 1: printf("Today is Monday"); case 2: printf("Today is Tuesday"); case 3: printf("Today is Wednesday"); case 4: printf("Today is Thursday"); case 5: printf("Today is Friday"); case 6: printf("Today is Saturday"); case 7: printf("Today is Sunday"); default: printf("Only enter value 1 to 7"); } getch(); }
Output
Enter any number (1 to 7): 4 Today is Thursday Today is Friday Today is Saturday Today is Sunday
Note: In switch statement when you not use break keyword after any statement then all the case after matching case will be execute. In above code case 4 is match and after case 4 all case are execute from case-4 to case-7.
C Program for calculator
Example
#include<stdio.h> #include<conio.h> void main() { char choice; int a,b,res=0; clrscr(); printf("Enter first value: "); scanf("%d",&a); printf("\n Enter operator: "); choice=getch(); printf("\n Enter second value: "); scanf("%d",&b); switch(choice) { case '+': res=a+b; printf("Sum: %d",res); break; case '-': res=a-b; printf("Difference: %d",res); break; case '*': res=a*b; printf("Product: %d",res); break; case '/': res=a/b; printf("Quotient: %d",res); break; default: printf("Enter Valid Operator!!"); } getch(); }
Example
Enter First number: 6 Enter operator : + Enter Second number: 10 Sum: 16
Explanation: In above code choice=getch(); is used for scan or get one value by using getch() function from keyboard, and store is choice.
