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Control Statements in C++

Hey there! In this guide, we'll explore decision-making in C++. Conditional statements, also called decision control structures, like if, else if, else, and switch are used for making decisions in C programs.

Referred to as Decision-Making Statements, they assess one or more conditions and determine whether a block of code should be executed. These statements:

  • Guide the flow of program execution
  • Choosing the path based on evaluated conditions
  • Decision-making structures allow you to execute different blocks of code based on certain conditions.
  • C++ provides several constructs for decision-making, including if, else if, else, and switch.

1. The if Statement​

Syntax:​

if (condition) {
    // code to be executed if condition is true
}

Example:​

int num = 10;
if (num > 0) {
    std::cout << "The number is positive." << std::endl;
}

2. The if...else Statement​

Syntax:​

if (condition1) {
    // code to be executed if condition1 is true
} else if (condition2) {
    // code to be executed if condition2 is true
} else {
    // code to be executed if both conditions are false
}

Example:​

int num = -5;
if (num > 0) {
    std::cout << "The number is positive." << std::endl;
} else {
    std::cout << "The number is not positive." << std::endl;
}

3. The if...else if...else Statement​

Syntax:​

if (condition1) {
    // code to be executed if condition1 is true
} else if (condition2) {
    // code to be executed if condition2 is true
} else {
    // code to be executed if both conditions are false
}

Example:​

int num = 0;
if (num > 0) {
    std::cout << "The number is positive." << std::endl;
} else if (num < 0) {
    std::cout << "The number is negative." << std::endl;
} else {
    std::cout << "The number is zero." << std::endl;
}

4. The switch Statement​

Syntax:​

switch (expression) {
    case value1:
        // code to be executed if expression == value1
        break;
    case value2:
        // code to be executed if expression == value2
        break;
    default:
        // code to be executed if expression doesn't match any case
}

Example:​

int day = 3;
switch (day) {
    case 1:
        std::cout << "Monday" << std::endl;
        break;
    case 2:
        std::cout << "Tuesday" << std::endl;
        break;
    case 3:
        std::cout << "Wednesday" << std::endl;
        break;
    default:
        std::cout << "Not a valid day" << std::endl;
}

5. Nested if Statements​

Example:​

int num = 15;
if (num > 10) {
    std::cout << "The number is greater than 10." << std::endl;
    if (num > 20) {
        std::cout << "The number is also greater than 20." << std::endl;
    }
}

6. Conditional Operators​

C++ also supports conditional operators for compact decision-making.

Ternary Operator​

(condition) ? expression1 : expression2;

Example:​

int num = 10;
std::string result = (num > 0) ? "Positive" : "Non-positive";
std::cout << result << std::endl;

Understanding Control Statements structures in C++ is crucial for controlling the flow of your program and executing different actions based on conditions. Happy coding!