Keep saying The variable 'width' is being used without being initialized.
#include <iostream>
#include <cmath>
using namespace std;
int main()
{
float length;
float width;
float area;
cout << "Enter The Length Of The Rectangle: ";
cin >> length;
area=length*width;
cout <<"The area of the rectangle is : "<< area << endl;
return 0;
}