Basic syntax and functions from the C++ programming language.
#include <iostream>
using namespace std;
int main() {
cout << "Welcome To Itedvantage";
return 0;
}
It prints output on the screen used with the insertion operator.
cout << "This is C++ Programming";
It takes input from the user used with the extraction operator.
cin >> variable_name;
The data type is the type of data.
Typically a single octet (one byte). It is an integer type.
char variable_name;
The most natural size of integer for the machine.
int variable_name;
A single-precision floating-point value.
float variable_name;
A double-precision floating-point value.
double variable_name;
Represents the absence of the type.
void
bool
It is a sequence of characters starting with a backslash, and it doesn’t represent itself when used inside a string literal.
It produces a beep sound.
cout << "\a";
It adds a backspace.
cout << "\b";
cout << "\f";
Newline Character.
cout << "\n";
cout << "\r";
It gives a tab space.
cout << "\t";
It adds a backslash.
cout << "\\";
It adds a single quotation mark.
cout << "\'";
It adds a question mark.
cout << "\?";
It represents the value of an octal number..
cout << "\nnn";
It represents the value of a hexadecimal number.
cout << "\xhh";
The null character is usually used to terminate a string.
cout << "\0";
A comment is a code that is not executed by the compiler, and the programmer uses it to keep track of the code.
// It's a single line comment
/* It's a
multi-line
comment
*/
It is a collection of characters surrounded by double quotes.
// Include the string library
#include
// String variable
string variable1 = "Hello World";
It is used to concatenate two strings.
string firstName = "Rocky";
string lastName = "Bhai";
string fullName = firstName.append(lastName);
cout << fullName;
It returns the length of the string.
string variable1 = "Itedvantage";
cout << "The length of the string is: " << variable1.length();
string variable1 = "Hello World";
variable1[1] = 'i';
cout << variable1;
C++ provides some built-in math functions that help the programmer to perform mathematical operations efficiently.
It returns the larger value among the two.
cout << max(25, 140);
It returns the smaller value among the two.
cout << min(55, 50);
It returns the square root of a supplied number.
#include
cout << sqrt(144);
It returns the value of x rounded up to its nearest integer.
double a = ceil(1.9);
It returns the value of x rounded down to its nearest integer.
double a = floor(1.02);
It returns the value of x to the power of y.
int a = pow(x, y);
Conditional statements are used to perform operations based on some condition.
if (condition) {
// This block of code will get executed, if the condition is True
}
if (condition) {
// If condition is True then this block will get executed
} else {
// If condition is False then this block will get executed
}
if (condition) {
// Statements;
} else if (condition) {
// Statements;
} else {
// Statements
}
It is shorthand of an if-else statement.
variable = (condition) ? expressionTrue : expressionFalse;
It allows a variable to be tested for equality against a list of values (cases).
switch (expression) {
case constant-expression:
statement1;
statement2;
break;
case constant-expression:
statement;
break;
...
default:
statement;
}
Iterative statements facilitate programmers to execute any block of code lines repeatedly and can be controlled as per conditions added by the programmer.
It iterates the block of code as long as a specified condition is True.
while (/* condition */) {
/* code block to be executed */
}
It is an exit controlled loop. It is very similar to the while loop with one difference, i.e., the body of the do-while loop is executed at least once even if the condition is False.
do {
/* code */
} while (/* condition */);
It is used to iterate the statements or a part of the program several times. It is frequently used to traverse the data structures like the array and linked list.
for (int i = 0; i < count; i++) {
/* code */
}
break keyword inside the loop is used to terminate the loop.
break;
continue keyword skips the rest of the current iteration of the loop and returns to the starting point of the loop.
continue;
Reference is an alias for an already existing variable. Once it is initialized to a variable, it cannot be changed to refer to another variable. So, it’s a const pointer.
string var1 = "Value1"; // var1 variable
string &var2 = var1; // reference to var1
Pointer is a variable that holds the memory address of another variable.
datatype *var_name;
var_name = &variable2;
Functions are used to divide an extensive program into smaller pieces. It can be called multiple times to provide reusability and modularity to the C program.
return_type function_name(data_type parameter...) {
// code to be executed
}
function_name(arguments);
Recursion is when a function calls a copy of itself to work on a minor problem. And the function that calls itself is known as the Recursive function.
void recurse() {
... .. ...
recurse();
... .. ...
}
It is a programming approach that primarily focuses on using objects and classes. The objects can be any real-world entities.
class Class_name {
public: // Access specifier
// fields
// functions
// blocks
};
Class_name ObjectName;
It is a special method that is called automatically as soon as the object is created.
class className { // The class
public: // Access specifier
className() { // Constructor
cout << "Itedvantage";
}
};
int main() {
className obj_name;
return 0;
}
Data encapsulation is a mechanism of bundling the data, and the functions that use them and data abstraction is a mechanism of exposing only the interfaces and hiding the implementation details from the user.
#include
using namespace std;
class ExampleEncap {
private:
/* Since we have marked these data members private,
* any entity outside this class cannot access these
* data members directly, they have to use getter and
* setter functions.
*/
int num;
char ch;
public:
/* Getter functions to get the value of data members.
* Since these functions are public, they can be accessed
* outside the class, thus provide the access to data members
* through them
*/
int getNum() const {
return num;
}
char getCh() const {
return ch;
}
/* Setter functions, they are called for assigning the values
* to the private data members.
*/
void setNum(int num) {
this->num = num;
}
void setCh(char ch) {
this->ch = ch;
}
};
int main() {
ExampleEncap obj;
obj.setNum(100);
obj.setCh('A');
cout << obj.getNum() << endl;
cout << obj.getCh() << endl;
return 0;
}
File handling refers to reading or writing data from files. C++ provides some functions that allow us to manipulate data in the files.
#include
#include
using namespace std;
int main() {
// Create and open a text file
ofstream MyFile("filename.txt");
// Write to the file
MyFile << "File Handling in C++";
// Close the file
MyFile.close();
}
It allows us to read the file line by line.
getline()
It opens a file in the C++ program.
void open(const char* file_name, ios::openmode mode);
Opens the file to read (default for ifstream).
fs.open("test.txt", std::fstream::in);
Opens the file to write (default for ofstream).
fs.open("test.txt", std::fstream::out);
Opens the file in binary mode.
fs.open("test.txt", std::fstream::binary);
Opens the file and appends all the outputs at the end.
fs.open("test.txt", std::fstream::app);
Opens the file and moves the control to the end of the file.
fs.open("test.txt", std::fstream::ate);
Removes the data in the existing file.
fs.open("test.txt", std::fstream::trunc);
Opens the file only if it already exists.
fs.open("test.txt", std::fstream::nocreate);
Opens the file only if it does not already exist.
fs.open("test.txt", std::fstream::noreplace);
It closes the file.
myfile.close();
An exception is an unusual condition that results in an interruption in the flow of the program.
A basic try-catch block in C++. When the try block throws an error, the control goes to the catch block.
try {
// code to try
throw exception; // If a problem arises, then throw an exception
}
catch () {
// Block of code to handle errors
}