C++ Switch Statements


title: Switch Statement

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.

Syntax:

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 or enumerated type(int,char,enum), or be of a class type in which the class has a single conversion function to an integral or enumerated 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 equal to a 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. The position of default block doesn’t matter, it is automatically executed if no match is found.

Two case labels cannot have the same value.

Example:

#include <iostream> using namespace std; int main () { // local variable declaration: char grade = 'D'; /* You can also have the user enter the value of grade to make your code more dynamic, like so: char grade; cin >> grade; */ switch(grade) { case 'A' : cout << "Excellent!" << endl; break; case 'B' : case 'C' : cout << "Well done" << endl; break; case 'D' : cout << "You passed" << endl; break; case 'F' : cout << "Better try again" << endl; break; default : cout << "Invalid grade" << endl; } cout << "Your grade is " << grade << endl; return 0; }
Output: You passed Your grade is D

Sources

https://www.tutorialspoint.com

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