//*****************************************************************
//Programer: Paul Gardiner
//Date: 26/05/2022
//Software:
//Platform: Microsoft Windows 10 Home
//Purpose: an app that takes user input to determine
//          the volume of a can, or area of a cans label.
//*****************************************************************

#include <iostream>
#include <cmath>
#include <iomanip>


using namespace std;


int
main ()
{
  //Initialise up variables
  double height = 0, radius = 0, volume = 0, area = 0;
  
  //ask for a height and radius
  cout << "Enter Can Height:";
  cin >> height;
  
  cout << "Enter Can Radius:";
  cin >> radius;
  
  //Formular for volume and area, M_PI is pi
  volume = (M_PI * (radius * radius) * height) / 1000;
  area = (M_PI * (2 * radius) * height);
  
  //Rounds the results to the second decimal place by * & / 100
  volume = round(volume*100)/100;
  area = round(area*100)/100;
  
  cout << "The Cans Volume is: " << volume << " litres.";
  cout << "The Labels Area is: " << area << " cm2";

  return 0;
}

C++ Online Compiler

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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
}