Decision Making

Decision-making is a fundamental aspect of programming, allowing programs to execute different code paths based on certain conditions. In C++, decision-making is implemented using constructs like if, else, and switch.

The if Statement

The if statement is used to execute a block of code if a specified condition is true. It can be followed by an optional else statement to execute a block of code if the condition is false.

				
					#include <iostream>

int main() {
    int x = 10;
    if (x > 5) {
        std::cout << "x is greater than 5" << std::endl;
    } else {
        std::cout << "x is not greater than 5" << std::endl;
    }
    return 0;
}

				
					// output //
x is greater than 5

Explanation:

In this example, the condition x > 5 is evaluated.
Since x is 10, which is greater than 5, the code block inside the if statement is executed.

The else-if Statement

The else-if statement allows for multiple conditions to be checked sequentially after an initial if statement.

				
					#include <iostream>

int main() {
    int x = 10;
    if (x > 10) {
        std::cout << "x is greater than 10" << std::endl;
    } else if (x < 10) {
        std::cout << "x is less than 10" << std::endl;
    } else {
        std::cout << "x is equal to 10" << std::endl;
    }
    return 0;
}

				
					// output //
x is equal to 10

Explanation:

The condition x > 10 is false, so the program checks the next condition.
The condition x < 10 is also false, so the program executes the code block inside the else statement.

Nested if Statements

You can nest if statements within other if or else statements to create more complex decision-making structures.

				
					#include <iostream>

int main() {
    int x = 10;
    if (x >= 0) {
        if (x % 2 == 0) {
            std::cout << "x is a positive even number" << std::endl;
        } else {
            std::cout << "x is a positive odd number" << std::endl;
        }
    } else {
        std::cout << "x is negative" << std::endl;
    }
    return 0;
}

				
					// output //
x is a positive even number

Explanation:

The outer if statement checks if x is non-negative.
If x is non-negative, the inner if statement checks if it is even or odd.

The else-if Ladder

The else-if ladder allows for multiple conditions to be checked sequentially after an initial if statement. It provides a structured way to handle multiple possible outcomes based on different conditions.

				
					#include <iostream>

int main() {
    int x = 10;
    if (x > 10) {
        std::cout << "x is greater than 10" << std::endl;
    } else if (x < 10) {
        std::cout << "x is less than 10" << std::endl;
    } else {
        std::cout << "x is equal to 10" << std::endl;
    }
    return 0;
}

				
					// output //
x is equal to 10

Explanation:

The condition x > 10 is false, so the program checks the next condition.
The condition x < 10 is also false, so the program executes the code block inside the else statement.
The else-if ladder provides a structured approach to handling multiple conditions in a sequential manner. Each condition is evaluated only if the previous condition(s) are false, ensuring that only one code block is executed based on the first true condition encountered.

The switch Statement

The switch statement in C++ provides a convenient way to perform multi-way branching based on the value of an expression. It allows you to execute different code blocks depending on the value of a variable or an expression.

				
					switch (expression) {
    case value1:
        // code block for value1
        break;
    case value2:
        // code block for value2
        break;
    // more case statements
    default:
        // default code block
}

expression: A variable or an expression whose value is to be compared with the values specified in the case labels.
value1, value2, etc.: Constants or integer values against which the expression is compared.
case: Label specifying a particular value to match.
default: Optional label specifying the code block to execute if no case label matches the expression.
break: Keyword used to exit the switch statement after executing a code block.

				
					#include <iostream>

int main() {
    int choice;
    std::cout << "Enter a number (1-3): ";
    std::cin >> choice;
    
    switch (choice) {
        case 1:
            std::cout << "You chose option 1" << std::endl;
            break;
        case 2:
            std::cout << "You chose option 2" << std::endl;
            break;
        case 3:
            std::cout << "You chose option 3" << std::endl;
            break;
        default:
            std::cout << "Invalid choice" << std::endl;
    }
    
    return 0;
}

				
					// output //
Enter a number (1-3): 2
You chose option 2

Explanation:

The user is prompted to enter a number.
The value entered by the user is stored in the choice variable.
The switch statement evaluates the value of choice.
If choice matches any of the case labels (1, 2, or 3), the corresponding code block is executed.
If no case label matches the value of choice, the code block under the default label is executed.
The break statement is used to exit the switch statement after executing the corresponding code block, preventing fall-through to subsequent case labels.

Key Points:

The switch statement provides a concise and readable way to handle multiple possible outcomes based on the value of an expression.
Each case label must be followed by a break statement to prevent fall-through to subsequent case labels.

Decision-making constructs such as if, else, and switch are essential tools in C++ programming for controlling the flow of execution based on conditions. By understanding how to use these constructs effectively, you can write more versatile and dynamic programs to meet various requirements.Happy coding! ❤️

Decision Making

The if Statement

Explanation:

The else-if Statement

Explanation:

Nested if Statements

Explanation:

The else-if Ladder

Explanation:

The switch Statement

Explanation:

Key Points:

Table of Contents

Explore

Popular Tutorials

Contact here