🔁 C++ Control Flow – Master if, switch, loops, break, and goto

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🧲 Introduction – What Is Control Flow in C++?

Control flow in C++ refers to the order in which individual statements, instructions, or function calls are executed or evaluated. By default, C++ programs execute code line by line, but control flow statements allow you to make decisions, repeat operations, or alter the normal flow based on conditions or loops.

🎯 In this guide, you’ll learn:

• The key types of control flow in C++
• How to use decision-making and loops effectively
• Where break, continue, and goto fit in
• The importance of readable and structured control logic

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📘 Topics Covered

🔹 Topic	📄 Description
🔃 C++ Control Statements	Grouping of all flow-controlling statements in C++
🔀 if / if-else Statements	Conditional branching
🧩 Nested if Statements	Conditions within conditions
🎚️ switch Statement	Multi-way branching using constant values
🔁 for Loop	Repeats a block a known number of times
🔄 while Loop	Repeats a block while a condition is true
🔂 do-while Loop	Executes at least once, then checks condition
🔃 foreach Loop	Iterates over collections using STL or ranges
🧬 Nested Loops	Loops inside loops for matrix/data iteration
⛔ break and continue	Exit or skip part of loops
🔀 goto Statement	Jumps to a labeled part of code (use discouraged)

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🧭 Categories of C++ Control Flow Statements

C++ control flow can be grouped into three categories:

🧩 Category	🔧 Statement Types
🧠 Decision-Making	if, if-else, nested if, switch, nested switch
🔁 Looping / Iteration	for, while, do-while, foreach (via STL or C++ ranges)
⛔ Jump / Branching	break, continue, goto

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🧩 1. Decision-Making Statements

These statements execute different code paths based on conditions.

✅ if / if-else

int marks = 85;
if (marks >= 40)
    cout << "Pass";
else
    cout << "Fail";

🧩 Nested if

if (x > 0) {
    if (x < 100) {
        cout << "Positive and less than 100";
    }
}

🎚️ switch / Nested switch

switch (grade) {
    case 'A': cout << "Excellent"; break;
    case 'B': cout << "Good"; break;
    default: cout << "Invalid";
}

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🔁 2. Looping Statements

Used to execute code repeatedly.

🔂 for Loop

for (int i = 0; i < 5; i++) {
    cout << i << " ";
}

🔄 while Loop

int i = 0;
while (i < 5) {
    cout << i << " ";
    i++;
}

🔁 do-while Loop

int i = 0;
do {
    cout << i << " ";
    i++;
} while (i < 5);

🔃 foreach Loop (STL-based)

vector<int> nums = {1, 2, 3};
for (int n : nums) {
    cout << n << " ";
}

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🧬 Nested Loops

for (int i = 0; i < 3; i++) {
    for (int j = 0; j < 2; j++) {
        cout << i << "," << j << endl;
    }
}

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⛔ 3. Jump Statements

🔻 break

for (int i = 0; i < 10; i++) {
    if (i == 5) break;
    cout << i << " ";
}

🔸 continue

for (int i = 0; i < 5; i++) {
    if (i == 2) continue;
    cout << i << " ";
}

🔀 goto

goto end;
cout << "Skipped code";
end:
cout << "Reached label";

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📘 Control Flow Example

int x = 10;
if (x > 0) {
    for (int i = 0; i < x; i++) {
        if (i == 5) break;
        cout << i << " ";
    }
}

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📌 Summary – Recap & Next Steps

🔍 Key Takeaways:

• C++ control flow governs what code runs and when
• if, switch, and loop constructs help control logic
• break, continue, and goto alter execution paths inside loops

Control flow is the engine behind decision-making and repetition in every C++ program. By mastering these constructs, you can write flexible, efficient, and structured code that reacts logically to data and conditions.

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❓ FAQs – C++ Control Flow

❓ What is control flow in programming?
✅ Control flow is the sequence in which statements are executed in a program.

❓ When should I use switch over if?
✅ Use switch when checking one variable against multiple constant values. It’s more efficient and readable.

❓ Can I use a loop inside another loop in C++?
✅ Yes, this is called nested loops, useful in matrices, patterns, and grids.

❓ Is goto recommended in C++?
✅ No. goto is discouraged as it can lead to unreadable code. Use loops and functions instead.

❓ What’s the difference between while and do-while?
✅ while checks the condition before execution. do-while checks it after, so it runs at least once.

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