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C++ Switch Statement
Introduction to Switch Statement:
The switch statement in C++ allows for the execution of one block of code among multiple options based on the value of a variable. It is an alternative to using multiple if-else statements and is particularly useful when you have a variable that can take one of many distinct values.
Basic Structure:
The switch statement evaluates an expression and executes the block of code associated with the matching case label. If no case matches, the default block, if present, is executed.
Syntax:
switch(expression) {
case constant1:
// Code to execute if expression equals constant1
break;
case constant2:
// Code to execute if expression equals constant2
break;
// You can have any number of case statements
default:
// Code to execute if none of the cases match
}
Example 1: Simple Switch
Understanding a Basic Switch:
Here is a simple example of a switch statement where the variable day is checked against several case labels to print the name of the day.
#include <iostream>
using namespace std;
int main() {
int day = 4;
switch(day) {
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;
default:
cout << "Invalid day";
}
return 0;
}
Console Output:
Thursday
Example 2: Switch with Default Case
Incorporating a Default Case:
The default case in a switch statement is executed when none of the case values match the expression. It is optional but recommended for handling unexpected values.
#include <iostream>
using namespace std;
int main() {
int month = 13;
switch(month) {
case 1:
cout << "January";
break;
case 2:
cout << "February";
break;
// Other cases omitted for brevity
case 12:
cout << "December";
break;
default:
cout << "Invalid month";
}
return 0;
}
Console Output:
Invalid month
Example 3: Switch with Fall-Through
Exploring Fall-Through Behavior:
In C++, if you omit the break statement, the program will continue executing the following cases until it encounters a break or the end of the switch block. This is known as fall-through.
#include <iostream>
using namespace std;
int main() {
int number = 2;
switch(number) {
case 1:
cout << "One";
case 2:
cout << "Two";
case 3:
cout << "Three";
break;
default:
cout << "Not in range";
}
return 0;
}
Console Output:
TwoThree
Example 4: Nested Switch Statements
Using Nested Switch Statements:
Switch statements can be nested inside one another. This is useful when you need to evaluate multiple conditions in a hierarchical manner.
#include <iostream>
using namespace std;
int main() {
int outer = 1, inner = 2;
switch(outer) {
case 1:
cout << "Outer is 1\n";
switch(inner) {
case 1:
cout << "Inner is 1";
break;
case 2:
cout << "Inner is 2";
break;
}
break;
default:
cout << "Outer is not 1";
}
return 0;
}
Console Output:
Outer is 1
Inner is 2
Example 5: Switch with Character Cases
Switch with Character Data Types:
Switch statements can also be used with character data types. Here is an example where a character variable is evaluated in a switch statement.
#include <iostream>
using namespace std;
int main() {
char grade = 'B';
switch(grade) {
case 'A':
cout << "Excellent!";
break;
case 'B':
cout << "Good";
break;
case 'C':
cout << "Fair";
break;
default:
cout << "Invalid grade";
}
return 0;
}
Console Output:
Good
Example 6: Switch with Enum Types
Utilizing Enums with Switch:
Enums provide a way to define named integer constants. Switch statements can be used to handle different enum values, improving code readability.
#include <iostream>
using namespace std;
enum Direction { UP, DOWN, LEFT, RIGHT };
int main() {
Direction dir = LEFT;
switch(dir) {
case UP:
cout << "Moving up";
break;
case DOWN:
cout << "Moving down";
break;
case LEFT:
cout << "Moving left";
break;
case RIGHT:
cout << "Moving right";
break;
default:
cout << "Invalid direction";
}
return 0;
}
Console Output:
Moving left
Example 7: Switch Without Break
Implications of Omitting Break:
Omitting the break statement can lead to fall-through behavior, where multiple case blocks are executed. This can be intentional for executing the same code for multiple cases.
#include <iostream>
using namespace std;
int main() {
int score = 3;
switch(score) {
case 1:
case 2:
case 3:
cout << "Low score";
break;
case 4:
case 5:
cout << "High score";
break;
default:
cout << "Invalid score";
}
return 0;
}
Console Output:
Low score
Example 8: Switch with Multiple Cases
Handling Multiple Cases with Same Code:
Sometimes, multiple cases require the same execution block. This can be efficiently handled by grouping cases together without a break in between.
#include <iostream>
using namespace std;
int main() {
char vowel = 'e';
switch(vowel) {
case 'a':
case 'e':
case 'i':
case 'o':
case 'u':
cout << "It's a vowel";
break;
default:
cout << "It's a consonant";
}
return 0;
}
Console Output:
It's a vowel
