C++ is a general-purpose programming language created by Bjarne Stroustrup as an extension of the C programming language, or "C with Classes".
The language has expanded significantly over time, and modern C++ now has object-oriented, generic, and functional features in addition to facilities for low-level memory manipulation. It is almost always implemented as a compiled language.
| C | C++ |
|---|---|
| C was developed by Dennis Ritchie between 1969 and 1973. | C++ was developed by Bjarne stroustrup in 1979. |
| C is (mostly) a subset of C++. | C++ is (mostly) a superset of C. |
| Is supports Procedural Programming. | It Support both Procedural and object Oriented Programming. |
| It Does not support Information hiding and encapsulation. | It does support Information hiding and encapsulation. |
| It is function-driven language. | It is Object-drivedn language. |
| Standard I/O header is <stdio.h>. | Standard I/O header is <iostream.h>. |
| It provides Malloc() and Calloc() for memory allocation | It provides New operator for memory allocation |
| It provides free() for Memory de-allocation. | It provides Delete |
// Output(print) in C
int a = 10;
printf("%d",a);
// Output(print) in C++
int a = 10;
cout<<a<<endl;
// Input value in C
int a;
scanf("%d",a);
// Input value in C++
int a;
cin>>a;const modifier is used to create constants.
Variables whose value cannot be changed once they are initalized.
Syntax:
const type variable_name = value;
example:
int main()
{
const int i = 10;
i = 20 // Error ! Cann't change value of i
// (since it is a constant)
}
Literals are data used for representing fixed point values that we can directly use in the code.
example:
10, 20, 3.14, 'a', etc.
-
Integer Literal
- Decimal Literal examples: 0, -1, 100, 20, etc. - Octal Literal (starts with 0) examples: 045, 065, 043 , etc. - Hexadecimal Literal (starts with 0x) examples: 0x8f, 0x2a, 0x721, etc. - Floating Point Literal It has a integer part, a decimal point, a fractional part , and an exponent part. example: 3.14134, 4e-11 , 1E-5, -
Boolean Literal
- true - false
-
Character Literal
- 'a' - 'b' - 'c'
-
String Literal
- "Hello World" - "C++"
Qualifiers are used to modify the meaning of the type.
- const : It is used to create constants.
- volatile : It is used to modify the variable.
- restrict : It is used to restrict the pointer.
Operators are used to perform operations on variables and values.
- Arithmetic Operators
- Addition (+) - Subtraction (-) - Multiplication (*) - Division (/) - Modulus (%) - Increment (++) - Decrement (--)
- Relational Operators
- Equal to (==) - Not equal to (!=) - Greater than (>) - Less than (<) - Greater than or equal to (>=) - Less than or equal to (<=) - Logical Operators
- Logical AND (&&) - Logical OR (||) - Logical NOT (!) - Bitwise Operators
- Bitwise AND (&) - Bitwise OR (|) - Bitwise XOR (^) - Bitwise NOT (~) - Bitwise Left Shift (<<) - Bitwise Right Shift (>>) - Assignment Operators
- Assignment (=) - Addition Assignment (+=) - Subtraction Assignment (-=) - Multiplication Assignment (*=) - Division Assignment (/=) - Modulus Assignment (%=) - Left Shift Assignment (<<=) - Right Shift Assignment (>>=) - Bitwise AND Assignment (&=) - Bitwise OR Assignment (|=) - Bitwise XOR Assignment (^=) - Miscellaneous Operators
- Sizeof - Comma (,) - Ternary (?) - Pointer to member (.*) - Member of pointer (->*) - Conditional Operator
Syntax: condition ? expression1 : expression2;example: int a = 10; int b = 20; int c = a > b ? a : b; cout<<c<<endl; - sizeof Operator
Syntax: sizeof (type)example: int a = 10; cout<<sizeof(a)<<endl; - Comma Operator
Syntax: expression1, expression2, expression3, ....example: int a = 10, b = 20, c = 30; cout<<a<<b<<c<<endl; - Pointer to member Operator
Syntax: object.*pointer_to_memberexample: class A { int a; public: void set(int x) { a = x; } int get() { return a; } }; int main() { A obj; obj.set(10); int A::*p = &A::a; cout<<obj.*p<<endl; } - Member of pointer Operator
Syntax: pointer->*pointer_to_memberexample: class A { int a; public: void set(int x) { a = x; } int get() { return a; } }; int main() { A obj; obj.set(10); int A::*p = &A::a; cout<<obj->*p<<endl; } - Type Casting Operator
Syntax: (type) expressionexample: int a = 10; float b = (float) a; cout<<b<<endl; - Precedence and Associativity of Operators
Precedence: 1. () 2. ++, -- 3. *, /, % 4. +, - 5. <<, >> 6. <, <=, >, >= 7. ==, != 8. & 9. ^ 10. | 11. && 12. || 13. ?: 14. =, +=, -=, *=, /=, %=, <<=, >>=, &=, ^=, |=Associativity: 1. Left to Right 2. Right to Left
Reference variable is an alias/another name of another variable.
Syntax:
type &reference_variable = variable;example:
int a = 10;
int &b = a;A function is a group of statements that together perform a task.
Syntax:
return_type function_name (parameter list)
{
body of the function
}example:
int add(int a, int b)
{
return a + b;
}Default arguments are used to provide default values to the parameters of a function.
Syntax:
return_type function_name (parameter list = default_value)
{
body of the function
}example:
int add(int a, int b = 10)
{
return a + b;
}
int main(){
cout<<add(10)<<endl; // This will print 20
}Inline function is an enhancement feature that improves the execution time and speed of a program.
Syntax:
inline return_type function_name (parameter list)
{
body of the function
}example:
inline int add(int a, int b)
{
return a + b;
}
int main(){
cout<<add(10, 20)<<endl; // This will print 30
}When a function is called, the values of the actual parameters are copied to the formal parameters of the function. This is called parameter passing by value.
example:
void swap(int a, int b)
{
int temp = a;
a = b;
b = temp;
}
int main(){
int a = 10, b = 20;
swap(a, b);
cout<<a<<b<<endl; // This will print 10 20
}When a function is called, It will give the address of the actual parameters to the formal parameters of the function. This is called parameter passing by reference.
It allows a function to modify a variable without having to create a copy of it.
example:
void swap(int &a, int &b)
{
int temp = a;
a = b;
b = temp;
}
int main(){
int a = 10, b = 20;
swap(a, b);
cout<<a<<b<<endl; // This will print 20 10
}When a function is called, It will pass the memory location of the actual parameters to the formal parameters of the function. This is called parameter passing by pointer.
example:
void swap(int *a, int *b)
{
int temp = *a;
*a = *b;
*b = temp;
}
int main(){
int a = 10, b = 20;
swap(&a, &b);
cout<<a<<b<<endl; // This will print 20 10
}Difference between Parameter Passing by Reference and Pointer
| Parameter Passing by Reference | Parameter Passing by Pointer |
|---|---|
| It is easy to use. | It is difficult to use. |
| It is faster than pointer. | It is slower than reference. |
| It is safer than pointer. because it cannot be NULL. | It is not safer than reference. |
New and delete operator are used to allocate and deallocate memory dynamically.
Syntax:
new data_type;
delete pointer;example:
int *p = new int;
*p = 10;
cout<<*p<<endl; // This will print 10
delete p;