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C Basics
course content

Course Content

C Basics

C Basics

1. Introduction
Structure of the C-ProgramEssentials of C ProgramHow to Run the Program?
2. Data
DataVariablesPrintfIntroduction to ArraysTwo Dimensional ArraysChar and StringSizeofPrintf PracticeSizeof Practice
3. Operators
Assignment, Comparison, Not Equal ToSum, Difference, Increment, DecrementMultiplication, Division and ModuloComparison OperatorsComparison Operators PracticeLogical OperatorsLogical Operators Practice
4. Control Statements
If-else Operatorif-else Operator PracticeTernary OperatorSwitch, BreakWhile, Do-WhileFor, ContinueFor Loop Practice
5. Functions
Structure of the FunctionDeclaration, Type and ReturnArgumentsPassing ArgumentsHeader, Prototypes Void, Recursion
6. Pointers
Pointers are around UsReferences and DereferencesPointersMalloc and FreeFunctions, Arrays and Two PointersVoid

References and Dereferences

Pointers are built around two operators:

  • The address-of operator &.
  • The dereference operator *.

Address-of Operator

The address-of operator, represented by &, allows us to directly interact with our computer's RAM. Using & lets you obtain the actual memory address of an object.

c

Main

copy

              
123456789101112

            
#include <stdio.h>

int main()
{
    int x = 100;

    printf("Value of variable: %d\n", x);

    printf("Address of variable into RAM: %p\n", &x); // using reference operator `&` for getting address

    return 0;
}

Note

%p is the format specifier used for addresses (pointer).

Addresses are typically expressed in hexadecimal notation.

Think of the & operator as identifying your home's address using your name.

Dereference Operator

Conversely, the * operator gives you the resident's name when given their address. So, how can we employ this operator if we're not directly dealing with addresses? If you have an expression like &x, which returns the address of the x variable, applying the * operator to it (*&x) gives you the value of the variable stored at that address.

Note

Essentially, *&x is the same as x.

c

Main

copy

              
1234567891011121314

            
#include <stdio.h>

int main()
{
    int x = 100;

    printf("Value of variable: %d\n", x);

    printf("Address of variable in RAM: %p\n", &x); // using reference operator `&`

    printf("Dereferencing address of variable: %d", *(&x)); // using dereference operator `*`

    return 0;
}

Note

Don't mix up the dereference operator (*x) with the multiplication operator (x*y).

Task

  • Create an integer array of 5 elements and populate it.
  • Retrieve the address of the third element.
  • Increment the address of the third element (i.e., address + 1).
  • Attempt to dereference the address obtained in the previous step.

Task

  • Create an integer array of 5 elements and populate it.
  • Retrieve the address of the third element.
  • Increment the address of the third element (i.e., address + 1).
  • Attempt to dereference the address obtained in the previous step.

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Section 6. Chapter 2
toggle bottom row

References and Dereferences

Pointers are built around two operators:

  • The address-of operator &.
  • The dereference operator *.

Address-of Operator

The address-of operator, represented by &, allows us to directly interact with our computer's RAM. Using & lets you obtain the actual memory address of an object.

c

Main

copy

              
123456789101112

            
#include <stdio.h>

int main()
{
    int x = 100;

    printf("Value of variable: %d\n", x);

    printf("Address of variable into RAM: %p\n", &x); // using reference operator `&` for getting address

    return 0;
}

Note

%p is the format specifier used for addresses (pointer).

Addresses are typically expressed in hexadecimal notation.

Think of the & operator as identifying your home's address using your name.

Dereference Operator

Conversely, the * operator gives you the resident's name when given their address. So, how can we employ this operator if we're not directly dealing with addresses? If you have an expression like &x, which returns the address of the x variable, applying the * operator to it (*&x) gives you the value of the variable stored at that address.

Note

Essentially, *&x is the same as x.

c

Main

copy

              
1234567891011121314

            
#include <stdio.h>

int main()
{
    int x = 100;

    printf("Value of variable: %d\n", x);

    printf("Address of variable in RAM: %p\n", &x); // using reference operator `&`

    printf("Dereferencing address of variable: %d", *(&x)); // using dereference operator `*`

    return 0;
}

Note

Don't mix up the dereference operator (*x) with the multiplication operator (x*y).

Task

  • Create an integer array of 5 elements and populate it.
  • Retrieve the address of the third element.
  • Increment the address of the third element (i.e., address + 1).
  • Attempt to dereference the address obtained in the previous step.

Task

  • Create an integer array of 5 elements and populate it.
  • Retrieve the address of the third element.
  • Increment the address of the third element (i.e., address + 1).
  • Attempt to dereference the address obtained in the previous step.

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Section 6. Chapter 2
toggle bottom row

References and Dereferences

Pointers are built around two operators:

  • The address-of operator &.
  • The dereference operator *.

Address-of Operator

The address-of operator, represented by &, allows us to directly interact with our computer's RAM. Using & lets you obtain the actual memory address of an object.

c

Main

copy

              
123456789101112

            
#include <stdio.h>

int main()
{
    int x = 100;

    printf("Value of variable: %d\n", x);

    printf("Address of variable into RAM: %p\n", &x); // using reference operator `&` for getting address

    return 0;
}

Note

%p is the format specifier used for addresses (pointer).

Addresses are typically expressed in hexadecimal notation.

Think of the & operator as identifying your home's address using your name.

Dereference Operator

Conversely, the * operator gives you the resident's name when given their address. So, how can we employ this operator if we're not directly dealing with addresses? If you have an expression like &x, which returns the address of the x variable, applying the * operator to it (*&x) gives you the value of the variable stored at that address.

Note

Essentially, *&x is the same as x.

c

Main

copy

              
1234567891011121314

            
#include <stdio.h>

int main()
{
    int x = 100;

    printf("Value of variable: %d\n", x);

    printf("Address of variable in RAM: %p\n", &x); // using reference operator `&`

    printf("Dereferencing address of variable: %d", *(&x)); // using dereference operator `*`

    return 0;
}

Note

Don't mix up the dereference operator (*x) with the multiplication operator (x*y).

Task

  • Create an integer array of 5 elements and populate it.
  • Retrieve the address of the third element.
  • Increment the address of the third element (i.e., address + 1).
  • Attempt to dereference the address obtained in the previous step.

Task

  • Create an integer array of 5 elements and populate it.
  • Retrieve the address of the third element.
  • Increment the address of the third element (i.e., address + 1).
  • Attempt to dereference the address obtained in the previous step.

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Pointers are built around two operators:

  • The address-of operator &.
  • The dereference operator *.

Address-of Operator

The address-of operator, represented by &, allows us to directly interact with our computer's RAM. Using & lets you obtain the actual memory address of an object.

c

Main

copy

              
123456789101112

            
#include <stdio.h>

int main()
{
    int x = 100;

    printf("Value of variable: %d\n", x);

    printf("Address of variable into RAM: %p\n", &x); // using reference operator `&` for getting address

    return 0;
}

Note

%p is the format specifier used for addresses (pointer).

Addresses are typically expressed in hexadecimal notation.

Think of the & operator as identifying your home's address using your name.

Dereference Operator

Conversely, the * operator gives you the resident's name when given their address. So, how can we employ this operator if we're not directly dealing with addresses? If you have an expression like &x, which returns the address of the x variable, applying the * operator to it (*&x) gives you the value of the variable stored at that address.

Note

Essentially, *&x is the same as x.

c

Main

copy

              
1234567891011121314

            
#include <stdio.h>

int main()
{
    int x = 100;

    printf("Value of variable: %d\n", x);

    printf("Address of variable in RAM: %p\n", &x); // using reference operator `&`

    printf("Dereferencing address of variable: %d", *(&x)); // using dereference operator `*`

    return 0;
}

Note

Don't mix up the dereference operator (*x) with the multiplication operator (x*y).

Task

  • Create an integer array of 5 elements and populate it.
  • Retrieve the address of the third element.
  • Increment the address of the third element (i.e., address + 1).
  • Attempt to dereference the address obtained in the previous step.

Switch to desktop for real-world practiceContinue from where you are using one of the options below
Section 6. Chapter 2
Switch to desktop for real-world practiceContinue from where you are using one of the options below
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