I am trying to write my first program in C++. I am receiving a code that I am not sure how to fix. I would appreciate the help! The code that I am receiving is : "error: expected primary-expression before "else".

I am getting the error after the else( choice ==2) portionCode:// Math Program - provides quick calculations to basic math problems #include <cstdio> #include <cstdlib> #include <iostream> using namespace std; // Function for factorial long factorial (long a) { if (a > 0) return (a * factorial (a-1)); else return (1); } int main() { // Header to program cout << "******************************" << endl; cout << "******** Math Program ********" << endl; cout << "******************************" << endl << endl; cout << "Please choose from the following options" << endl; cout << "1-Factorial" << endl; cout << "2-Slope of a Line" << endl; cout << endl << "Selection: "; int choice; cin >> choice; // Decide which function to run long number; if (choice == 1) { // Enter a number and call factorial() to provide answer cout << endl << "Please type a number: "; cin >> number; if(number < 0) { cout << "Enter a positive integer!..." << endl <<endl; } else { cout << number << "! = " << factorial (number) << endl << endl; } } long x1,x2,y1,y2; long slope; else if (choice == 2) // Enter coordinates and calculuates slope to provide answer { cout << endl << "Please enter the first set of coordinates: "; cin >> x1; cin >> y1; cout << endl << "Now enter the second set of coordinates: "; cin >> x2; cin >> y2; slope = ((y2-y1)/(x2-x1)); cout << "The slope of the line is:" << slope; } // Wait for user to respond to quit program system ("pause"); return 0;