#include <iostream>
#include<cmath>
#include<iomanip>
double lower_sum(double a, double b, long n);
double lower_sum(double a, double b, long n){

double s,h;
a=0,b=1;
//s=0;



s=(pow(M_E,b)-1)*((b-a)/n)/(pow(M_E,(b-a)/n)-1);

//s= (pow(M_E,b)-1)*(h)/(pow(M_E,h)-1);
//s=(pow(M_E,b)-1)*(pow(2,-(j+1)))/(pow(M_E,pow(2,-(j+1)))-1);
return s;
}
int main()
{
        std::cout<<"FORWARD DIFFERENCE"<<std::endl;
        std::cout<<"K";
        std::cout<<"\t STEP SIZE";
        std::cout<<"\t\t\t APPROX INTEGRAL";
        std::cout<<"\t ABSOLUTE ERROR";
        std::cout<<"\t\t LOG ERROR RATIO"<<std::endl;
    double r,z,y,e,x,h,a,b,n,s;
    double r1,z1,y1,e1;
    double r2,z2,y2,e2,c;
    for(int k = 0; k<=15;k++ ){
        
        
        n=(pow(2,k));
        h=1/n;
        e=pow(M_E,1)-pow(M_E,0)-(pow(M_E,1)-1)*(h)/(pow(M_E,h)-1);
        y=(pow(2,-k))/pow(2,-k+1);
        z=e/(pow(M_E,1)-pow(M_E,0)-(pow(M_E,1)-1)*pow(2,-k+1)/(pow(M_E,pow(2,-k+1))-1));
        r=log(z)/log(y);
       
        std::cout << std::fixed << std::setprecision(15);
        
        std::cout<<k<<"\t ";
        std::cout<<h<< "\t ";
        
        std::cout << lower_sum(a,b,n)<<"\t ";
        std::cout<<e<< "\t ";
        if (k==0)
        std::cout <<" "<<std::endl; 
        else 
        std::cout<<r<<std::endl;}

      
       
    return 0;
}

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
}