➕ C++ Unary Operators – Operate on a Single Operand

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🧲 Introduction – What Are Unary Operators in C++?

Unary operators in C++ operate on a single operand to perform operations such as incrementing, decrementing, negating, or logical testing. These operators are essential for loop control, logical expressions, pointer manipulation, and mathematical transformations.

🎯 In this guide, you’ll learn:

• The list and function of unary operators
• Pre- and post-increment/decrement usage
• Logical and address-related operators
• Common use cases and coding tips

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📋 List of C++ Unary Operators

Operator	Symbol	Description	Example
Unary plus	+	Returns the positive value (identity)	+a
Unary minus	-	Negates the value	-a
Logical NOT	!	Inverts a boolean value	!flag
Bitwise NOT	~	Inverts all bits	~x
Pre-increment	++a	Increments value before use	++i
Post-increment	a++	Increments value after use	i++
Pre-decrement	--a	Decrements value before use	--i
Post-decrement	a--	Decrements value after use	i--
Address-of	&	Returns the memory address	&x
Dereference	*	Accesses value at a pointer	*ptr

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✏️ Example – Pre vs Post Increment

int x = 5;

int a = ++x;  // x becomes 6, a = 6
int b = x++;  // b = 6, x becomes 7

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🧠 Logical NOT !

bool flag = false;
cout << !flag;  // Outputs 1 (true)

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🧠 Bitwise NOT ~

int a = 5;         // 00000101
int b = ~a;        // 11111010 (Two's complement of 6)

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📦 Address-of & and Dereference *

These are pointer-related unary operators:

int x = 100;
int* ptr = &x;  // Address-of
cout << *ptr;   // Dereference → outputs 100

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⚠️ Common Mistakes

❌ Mistake	✅ Fix
Confusing pre and post ops	Know when value changes vs when it’s returned
Dereferencing uninitialized pointers	Always assign valid address to pointer
Using ~ on float/double	Only use ~ on integers
Applying & on temporary values	Use & on actual variables, not rvalues

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📌 Summary – Recap & Next Steps

🔍 Key Takeaways:

• Unary operators work with a single operand
• Pre/post increment/decrement behave differently in expressions
• Logical and bitwise NOT serve distinct purposes
• * and & are critical in pointer operations

⚙️ Real-World Relevance:
Unary operators are used in looping constructs, bitmasking, boolean logic, and pointer dereferencing, making them fundamental to efficient and effective C++ coding.

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❓ FAQs – C++ Unary Operators

❓ What is the difference between ++i and i++?
✅ ++i increments before using the value; i++ increments after using it.

❓ Can I use ++ with float or double?
✅ Yes. All numeric types support ++ and --.

❓ What does ~ do to a number?
✅ It flips all the bits (bitwise complement), resulting in -n - 1.

❓ Are & and * also unary operators?
✅ Yes. & returns an address, * accesses the value at an address.

❓ Can I chain unary operators?
✅ Yes. Example: --*ptr decrements the value pointed to by ptr.

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