In this Tutorial we will understand and learn the working of C++ Switch Case Control Structure.
A switch statement allows a variable to be tested for equality against a list of values. Each value is called a case, and the variable being switched on is checked for each case.
Switch case statements are a substitute for long if statements that compare a variable to several “integral” values (“integral” values are simply values that can be expressed as an integer, such as the value of a char).
The condition of a switch statement is a value.
An important thing to note about the switch statement is that the case values may only be constant integral expressions.
Switch case conditions cannot contain conditional statements (>, <, <=,>=). It can only contain a constant integral value (not even floating point values)
Flowchart of Switch Case
Flow Chart diagram of Switch Case Structure
Basic Syntax of Switch Case statement
switch(expression){ case constant-expression : statement(s); break; //optional case constant-expression : statement(s); break; //optional // you can have any number of case statements. default : //Optional statement(s); }
The following rules apply to a switch statement:
- The expression used in a switch statement must have an integral type.
- You can have any number of case statements within a switch. Each case is followed by the value to be compared to and a colon.
- The constant-expression for a case must be the same data type as the variable in the switch, and it must be a constant or a literal.
- When the variable being switched on is to a equal case, the statements following that case will execute until a break statement is reached.
- When a break statement is reached, the switch terminates, and the flow of control jumps to the next line following the switch statement.
- Not every case needs to contain a break. If no break appears, the flow of control will fall through to subsequent cases until a break is reached.
- A switch statement can have an optional default case, which must appear at the end of the switch. The default case can be used for performing a task when none of the cases is true. No break is needed in the default case.
Example program of Switch Case statement
#include<iostream> using namespace std; int main() { int num; cout<<"Enter a Number between 1 and 7:"; cin>>num; switch(num) { case 1: cout<<"Monday"; break; case 2: cout<<"Tuesday"; break; case 3: cout<<"Wednesday"; break; case 4: cout<<"Thursday"; break; case 5: cout<<"Friday"; break; case 6: cout<<"Saturday"; break; case 7: cout<<"Sunday"; break; // optional default: cout<<"Invalid Input"; } // end of switch case return 0; }