What is the Difference between wild pointer and Dangling pointer ?

wild pointer : is uninitialized pointer , but dangling pointer is pointer that not assigned to NULL after freed it 

so how we can deal with this 

for wild pointer you need to make a general rule for you any pointer you will define it you need to initialize it to NULL. 

for dangling pointer you need also to assign NULL to any pointer after you freed its allocated memory.

what is the difference between declaration and definition ?

Declaration  not reserve any memory, it is just tells the compiler about some information about that object either ( variable - function ).

ex :  extern int x ; 

on the other hand definition is reserve memory for that object 

ex : int x ; 

declaration can be done multiple times but definition must be once.

Definition can be with initialization or not but declaration can not contain initialization.

ex : extern int x = 10 ; // compilation  error 

what is the difference between implicit and explicit type conversions in C ?

 implicit conversion : 

is done by compiler and this is done to prevent any loss  of data so this implicit conversion will maintain magnitude not sign 

bool -> char -> short -> int -> unsigned int -> long -> long long -> float -> double -> long double.

explicit conversion: 

is done by user and we need this always if we need to perform the operation with a specific data type also we can make implicit conversion as explicit to make it more readable so any other programmers can know what is going on here.

Comparing between const C keyword and #define for declaring a constant values?

#define :

it's not block scope and it is file scope from the point it's defined tell the end of the file.

it's preprocessor and it not take any size in memory so we can not obtain it's address.

there is no any type checking. 

what is the difference between Reentrant and Non Reentrant?

This function can be called by more than one task without ant fear of data corruption also can be interrupted many times without any feer of data loss.

Reentrant functions properties :

does not contain any global or static variables even if it can  use a global variables by with a protection mechanism 

must not call any a non reentrant function 

what is the difference between synchronous and asynchronous functions ?

synchronous function:

is he function that block the program until it executes and perform all data operations before return to the caller 

asynchronous function: 

is not a blocking function actually it is set some data then return to the caller immediately and the many operation on this data will be done later by another thread or runnable.

what is the difference between Scope and Linkage ?

Scope : 

is used by compiler to determine if we can access this variable  here or not.

linkage :

compiler will put all variables that has external linkage inside each file into a table than linker will solve these references for all tables  that is generated from all source files.

Declarations in C ?

generally any object (variable, function ) consistent of the following sections 

(storage class) (type qualifier) (type specifier) (identifier) ( ; )

storage class: extern , static , auto , register.

type qualifier: const , volatile , strict.

type specifier: int ,char ...etc.

identifier: the object name.

What is the different types of errors in C ? 

[ Syntax , Runtime , Linker , Logical , Symantec ] Errors.

Syntax Errors : 

Due to violate the C language writing rules. (Easy to trace and fix )

Runtime Error : 

Appear in Runtime of the program during execution phase ex (Divide by zero , stack overflow )

Linker Error:

this type of error is appear in linking phase after compiling phase example of some errors in this phase ( undefine reference , memory section overflow )

Logical Error:

this error is due to the program is not behave as expected due to programmer may be rely on undefined behavior or code not written as expected.

Symantec Error:

this type of error is due to the code is written well but it is no use or no meaning of it.

What is the effect of Static keyword with both of local and global variables?

with local variable 

it is effect on the memory stored location.

but with global variables: 

it is effect on the linkage of the variable where it is a static global variable it is file scope otherwise it is project scope.

What is the difference between the macro as a function and inline functions?