In C language, header files are used to organize and reuse code efficiently

6 Key uses of header files in C language are :

1. Function declarations (Prototypes)
2. Macro Definitions
3. Type Definitions
4. Structure Declarations
5. Code Reusability
6. Modularity

1. Pointers

• Why it's tough: Requires understanding of memory addresses, dereferencing, and pointer arithmetic, which are abstract and error-prone for beginners.

2. Dynamic Memory Allocation (malloc, calloc, free)

• Why it's tough: Involves manual memory management; mistakes can lead to memory leaks or crashes.

3. Pointers to Pointers (Double Pointers)

• Why it's tough: Adds an extra layer of indirection, making it confusing to visualize and debug.

4. Structures with Pointers

• Why it's tough: Mixing user-defined data types with pointers increases complexity in memory handling and data access.

5. Function Pointers

• Why it's tough: Syntax is tricky, and understanding how functions can be passed or referenced like variables is abstract.

6. Recursion

• Why it's tough: Logical thinking is required to trace function calls, especially for deeply nested recursive solutions.

7. Bit Manipulation

• Why it's tough: Involves low-level binary operations that require understanding of bitwise logic and masking.

8. File Handling

• Why it's tough: Includes working with file pointers and modes, and handling edge cases like file access errors.

'=' (Assignment Operator): The single equal sign = is used as an assignment operator. It is used to assign a value to a variable.

'==' (Equality Operator): The double equal sign == is used as a relational operator for equality. It is used to compare two values for equality.