What are Control Structures in C++| How to use if, else, switch
Introduction
Control structures are a fundamental aspect of programming that dictate the flow of a program's execution. Among these,
if, else, and switch statements are pivotal. This guide delves into the nuances of these control structures in C++, providing examples and insights to help you master their usage.
The if Statement
The if statement is one of the most basic and commonly used control structures in programming. It allows you to execute a block of code only if a specified condition is true.
if (condition) {
// Code to execute if condition is true
}For example, consider a simple scenario where we want to check if a number is positive:
| #include <iostream> |
| using namespace std; |
| int main() { |
| int number = 10; |
| if (number > 0) { |
| cout << "The number is positive." << endl; |
| } |
| return 0; |
| } |
The else Statement
The else statement complements the if statement. It provides an alternative block of code that executes if the if condition is false.
if (condition) {
// Code to execute if condition is true
} else {
// Code to execute if condition is false
}Continuing with our example, let's handle the case where the number is not positive:
| #include <iostream> |
| using namespace std; |
| int main() { |
| int number = -5; |
| if (number > 0) { |
| cout << "The number is positive." << endl; |
| } else { |
| cout << "The number is not positive." << endl; |
| } |
| return 0; |
| } |
The else if Statement
Sometimes, multiple conditions need to be checked sequentially. This is where else if comes into play.
if (condition1) {
// Code to execute if condition1 is true
} else if (condition2) {
// Code to execute if condition2 is true
} else {
// Code to execute if both conditions are false
}For instance, checking if a number is positive, negative, or zero:
| #include <iostream> |
| using namespace std; |
| int main() { |
| int number = 0; |
| if (number > 0) { |
| cout << "The number is positive." << endl; |
| } else if (number < 0) { |
| cout << "The number is negative." << endl; |
| } else { |
| cout << "The number is zero." << endl; |
| } |
| return 0; |
| } |
The switch Statement
The switch statement is an alternative to using multiple if else statements. It evaluates an expression and executes code based on the matching case.
switch (expression) {
case value1:
// Code to execute if expression == value1
break;
case value2:
// Code to execute if expression == value2
break;
// Additional cases
default:
// Code to execute if no case matches
}Let's use a switch statement to determine the day of the week:
| #include <iostream> |
| using namespace std; |
| int main() { |
| int day = 3; |
| switch (day) { |
| case 1: |
| cout << "Monday" << endl; |
| break; |
| case 2: |
| cout << "Tuesday" << endl; |
| break; |
| case 3: |
| cout << "Wednesday" << endl; |
| break; |
| case 4: |
| cout << "Thursday" << endl; |
| break; |
| case 5: |
| cout << "Friday" << endl; |
| break; |
| case 6: |
| cout << "Saturday" << endl; |
| break; |
| case 7: |
| cout << " Sunday" <<endl; |
| default: |
| cout << "Invalid day" <<endl; |
| } |
| return 0; |
| } |
Understanding if, else, and switch statements is crucial for controlling the flow of a program. These control structures enable programmers to handle various conditions efficiently and create more dynamic and responsive applications. Practice these constructs to enhance your coding proficiency and tackle more complex problems with ease.