The switch statement in C allows a variable to be tested for equality against multiple case labels, and allows for different blocks of code to be executed depending on which expression matches. It requires an expression of any type and then compares it against integer case constants. If no case matches, the default code block will execute. The syntax includes the switch keyword followed by an expression, then case labels and code blocks, with breaks to end each block. Variables and float values cannot be used as case labels.

1. Switch statement in C
Session By
V. Balamurugan, AP/CSE

2. Switch statememnt in C

3. Switch statement
• The switch() case statement is like the if statement
that allows us to make a decision from a number
of choices.
• The switch statement requires only one argument
of any data type, which is checked with a number
of case options.
• The switch statement evaluates the expression
and then looks for its value among case constants.
• If the value matches with a case constant, this
particular case statement is executed.
• If not, the default is executed.

4. Syntax
switch <expr>
{
case constant_1:
{
statements 1;
break;
}
case constant_2:
{
statements 2;
break;
}
default:
{
default statements;
}
}

6. Facts related to switch
• Duplicate cases are not allowed

7. Facts related to switch
• Only those expressions are allowed in switch which results in
an integral constant value

8. Facts related to switch
• Float value is not allowed as a constant value in case label.
Only integer constants/ constant expressions are allowed in
case label

9. Facts related to switch
• Variable expressions are not allowed in case labels. Although
macros are allowed

10. Facts related to switch
• Default can be placed anywhere inside the switch. It will still
get evaluated if no match is found
int main()
{
int x=2;
switch(x){
default: printf(“default case”);
break;
case 1: printf(“Number is 1”);
break;
case 2: printf(“Number is 2”);
break;
}
}

11. 11
V.BALAMURUGAN AP/CSE
Contact me @ 6383865268
Mail me @balamuruganv@acetcbe.edu.in