#include <iostream>
using namespace std;

// int main() 
// {
// //   int myNum = 5;               // Integer (whole number)
// // float myFloatNum = 5.99;     // Floating point number
// // double myDoubleNum = 9.98;   // Floating point number
// // char myLetter = 'D';         // Character
// // bool myBoolean = true;       // Boolean
// // string myText = "Hello";     // String
// }

// boolean 1 byte
//char 1 bytes
//int 2 or 4 bytes
//float 4 bytes
//double 8 bytes

//Double vs float
//Double can have upto 15 decimal points where as float only 6 or 7;
// int main(){
// double mynum=4.75;
// float myNum=4111.5555;
// cout<<mynum<<endl;
// cout<<myNum;
// }

//operators
//Arthemetic
// +	Addition	Adds together two values	x + y	
// -	Subtraction	Subtracts one value from another	x - y	
// *	Multiplication	Multiplies two values	x * y	
// /	Division	Divides one value by another	x / y	
// %	Modulus	Returns the division remainder	x % y	
// ++	Increment	Increases the value of a variable by 1	++x	
// --	Decrement	Decreases the value of a variable by 1	--x	


//Assignment
// =  	x = 5	  x = 5	
// +=	  x += 3	x = x + 3	
// -=	  x -= 3	x = x - 3	
// *=	  x *= 3	x = x * 3	
// /=	  x /= 3	x = x / 3	
// %=	  x %= 3	x = x % 3	
// &=	  x &= 3	x = x & 3	
// |=	  x |= 3	x = x | 3	
// ^=	  x ^= 3	x = x ^ 3	
// >>=	x >>= 3	x = x >> 3	
// <<=	x <<= 3	x = x << 3


//Comparison operators
// 0 means false 1 means true
// ==	Equal to	x == y	
// !=	Not equal	x != y	
// >	Greater than	x > y	
// <	Less than	x < y	
// >=	Greater than or equal to	x >= y	
// <=	Less than or equal to	x <= y
// int main(){
//   int x=4,y=10;
//   cout<<(x>y);returns 0 means false
// }


//Logical operators
//Used to find the logic between variables and values.
// && 	Logical and,Returns true if both statements are true	x < 5 &&  x < 10	
// || 	Logical or,	Returns true if one of the statements is true	x < 5 || x < 4	
// !	Logical not,	Reverse the result, returns false if the result is true	!(x < 5 && x < 10)

//Strings
// int main(){
//   string name="Ravindra";
//   cout<<name;
// }

//String Concatenation
// int main(){
//   string name="John ";
//   string fullname="Cena";
//   cout<<name+fullname;
// }

//String Concatenation by Append()
// int main(){
//   string name="John ";
//   string fullname="Smith";
//   cout<<name.append(fullname);
// }

//If number are used as strings then they will be concatenated
// int main(){
//   string x = "10";
// string y = "20";
// string z = x + y;
// cout<<z;//retursn 1020 Concatenation occurs
// }

//String and an int can be added
// int main(){
// string x = "10";
// int y = 20;
// string z = x + y;
// cout<<z;// Error
// }

//String length
//Both length and size are same
// int main(){
//   string goal="This is my goal";
//   // cout<<goal.length();
//   cout<<goal.size();
// }

//String Access
//You can access string elements same as std::array<T, N> ;
// int main(){
//   string greet="Hello";
//   cout<<greet[0];
// }

// Change String Characters
// int main(){
//   string greet="Hello";
//   greet[0]='g';
//   cout<<greet;
// }


//User Input strings
int main(){
  string name;
  cout<<"Enter Your name\n";
  cin>>name;
  cout<<"Your name is: "<<name;
}
by

C++ Online Compiler

Write, Run & Share C++ code online using OneCompiler's C++ online compiler for free. It's one of the robust, feature-rich online compilers for C++ language, running on the latest version 17. Getting started with the OneCompiler's C++ compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C++ and start coding!

Read inputs from stdin

OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.

#include <iostream>
#include <string>
using namespace std;

int main() 
{
    string name;
    cout << "Enter name:";
    getline (cin, name);
    cout << "Hello " << name;
    return 0;
}

About C++

C++ is a widely used middle-level programming language.

  • Supports different platforms like Windows, various Linux flavours, MacOS etc
  • C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
  • Case-sensitive
  • C++ is a compiler based language
  • C++ supports structured programming language
  • C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
  • Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}