function definition:

a block of code for a specific task.

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Function Declaration:

Ex:

int addNumbers(int x, int y);

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Function Calling:

Ex:

Int m = 5, n = 7;

int result = addNumbers(m,n);

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Function Definition:

Ex:

int addNumbers(int x, int y)
{
int sum = x + y;
return sum;
}

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Parameters:

the variables in the declaration and the definition of a function
(a, b).

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Arguments:

the value of the variables that are passed to the parameters

(m = 5, n = 7).

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Calling a function

Ex:

Add (m, n); // calling a function named add()

The actual function:

Add(int a, int b)

{

Return a+B;

}

m,n --> Actual parameters.

a,b --> Formal parameter.

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Calling By values:

the values of actual parameters are copied to formal parameters and stored in the formal parameters' Memory location.

Ex:

Int x = 10, y = 20;

Fun(x, y); //fun calling

Printf("%d %d", x, y);

The actual function:

int fun(int x, int y)
{
x = 50;
y= 70;
}

OUTPUT --> 10 20

Because after the function got executed, its parameters got destroyed and its value didn’t get assigned to a variable in the main(), so no place in the memory.

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Calling Buy references:

Both actual and formal parameters refer to the same memory location so any changes made to the formal parameter will get reflected in the  actual parameters.

so ---> Instead of passing values we pass addresses (pointers).

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Ex:

int x = 10, y = 20; Fun(&x, &y); // function calling
Printf("%d %d", x, y);

The actual function:

int fun(int **Ptr1, int **Ptr2) {
*Ptr1 = 50;
*Ptr2 = 70;
}

OUTPUT --> 50 70

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SO

• Referencing is the address of a variable (&) --> pointer.

• When we want the value of what that address (pointer) refers to,
  we want to((dereference)) it.
  So:
  we want to *&var which is *Ptr.

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Pointer Declaration:

int *ptr; // we tell the compiler to save memory space for a pointer named ptr.

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Pointer Assignment:

int x = 5; ptr = &x;

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Dereferencing a Pointer:

printf("The value of x is: %d", *ptr);

So, when we put all the parts together, the code will look like this:

#include <stdio.h>
int main()
{
int *ptr; int x = 5;

// Assigning the address of x to ptr
ptr = &x;
// Getting the value of the variable (x) which the pointer (ptr) refers to
printf("The value of x is: %d", *ptr);
return 0;
}

OUTPUT --> The value of x is: 5

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In conclusion,

Formal parameters (parameters),

Actual parameters(arguments),

And pointers

are essential concepts in C language that are used to pass information between variables. By using these concepts, C functions can communicate information and modify variables more efficiently and flexibly. Understanding these concepts is crucial for any C programmer who wants to write efficient and effective code.

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Hope it was helpful.