Untitled

#include<iostream>
#include<math.h>
#define f(x) 1/(1+pow(x,2))

using namespace std;
int main(){
	float lower, upper, integration=0.0, stepSize, k;
	int i, subInterval;
	
	cout<<"Enter lower limit of integration: "; cin>>lower;
	cout<<"Enter upper limit of integration: "; cin>>upper;
	cout<<"Enter number of sub intervals: ";    cin>>subInterval;

	stepSize = (upper - lower)/subInterval;

	integration = f(lower) + f(upper);
	
	for(i=1; i<= subInterval-1; i++){
		k = lower + i*stepSize;
		integration = integration + 2 * (f(k));
	}
	
	integration = integration * stepSize/2;
	
	cout<< endl<<"Required value of integration is: "<< integration;
	
	return 0;
}