🔀 C++ if / if-else Statements – Decision-Making in C++

🧲 Introduction – What Are if and if-else Statements?

The if and if-else statements in C++ are fundamental control structures that allow you to make decisions in your code. These statements evaluate a condition and execute blocks of code based on whether the condition is true or false.

🎯 In this guide, you’ll learn:

• Syntax of if and if-else
• Multiple condition handling with else if
• Practical examples and common patterns
• Best practices for writing clean decision-making logic

✅ Basic if Statement Syntax

if (condition) {
    // code to execute if condition is true
}

📌 Example:

int age = 20;
if (age >= 18) {
    cout << "Eligible to vote";
}

🔁 if-else Statement

Used when there are two possible outcomes (true/false).

if (condition) {
    // runs if true
} else {
    // runs if false
}

📌 Example:

int marks = 35;
if (marks >= 40) {
    cout << "Pass";
} else {
    cout << "Fail";
}

🔄 if – else if – else Chain

Used when there are multiple conditions to evaluate.

if (score >= 90) {
    cout << "A Grade";
} else if (score >= 75) {
    cout << "B Grade";
} else if (score >= 60) {
    cout << "C Grade";
} else {
    cout << "Fail";
}

🔁 Ternary Operator Alternative

For simple conditions, use:

string result = (marks >= 40) ? "Pass" : "Fail";

But avoid this for complex conditions—prefer if-else for clarity.

⚠️ Common Mistakes

🧠 Best Practices

• Always use braces {} even for single-line blocks
• Structure conditions from most likely to least likely
• Keep condition logic short and readable
• Use else if only when previous conditions fail

📌 Summary – Recap & Next Steps

🔍 Key Takeaways:

• if checks a condition and runs code if true
• if-else adds alternate behavior if the condition is false
• else if helps handle multiple decision paths
• Use braces {} and clear logic for maintainable code

⚙️ Real-World Relevance:
if and if-else statements are core to form validation, authentication, game logic, and business rules processing.

❓ FAQs – C++ if / if-else Statements

❓ Can I nest if statements?
✅ Yes, but use indentation and braces to keep it readable.

❓ What’s the difference between = and == in if?
✅ = assigns a value; == compares values.

❓ Is else if mandatory?
❌ No. You can use just if and else, or only if when needed.

❓ Can I write if without braces?
✅ Yes, but it’s bad practice unless it’s a one-liner.

❓ How many else if blocks can I have?
✅ As many as needed. But too many may indicate the need for switch.