#include <iostream>
#include "gurobi_c++.h"

using namespace std;

int main() {
	
	//8. Exception Handling
	try {
		//1.1 Basic elements declaration
		GRBEnv env = GRBEnv();
		GRBModel model= GRBModel(env);

		//1.2 Parameters definition
		const int N = 2;  //number of resources  
		const int M = 2; //number of products (D.V.)
		int a[N][M]= {{1, 2},
					  {4, 3}}; //coefficients in the constraints
		int b[N] = {40, 120};   //coefficients of the RHS (Right-Hand-Side)
		int c[M] = {40, 50};    //coefficients of objective function  


		//2. Decision Variables
		GRBVar x[M];
		for(int j=0; j<M; j++) {
			x[j] = model.addVar(0.0, GRB_INFINITY, 0.0, GRB_CONTINUOUS);
		}

		//3. Integrate variables into model
		model.update();

		//4. Constraint Declaration
		for(int i=0; i<N; i++) {
			 GRBLinExpr LHS=0;
			for(int j=0; j<M; j++) {
				LHS += a[i][j]*x[j];
			}
			model.addConstr(LHS,GRB_LESS_EQUAL,b[i]);
		}

		
		//5. set the model to maximization
		model.set(GRB_IntAttr_ModelSense,-1);

		GRBLinExpr Obj = 0;
		for(int j=0; j<M; j++) 
			Obj += c[j]*x[j];
		model.setObjective(Obj);

		//6. Optimize the model
		model.optimize();

		//7. Check Optimality and Output Results

		//7.1 Check Optimality  
		int status = model.get(GRB_IntAttr_Status);
		if (status == GRB_OPTIMAL) {
			
			//7.2 Output the objective value and solutions
			double ObjValue = model.get(GRB_DoubleAttr_ObjVal);
			cout<<"total cost= "<<ObjValue<<endl;

			for(int i=0; i<M; i++) {
				cout<<"x "<<i<<" ="<<x[i].get(GRB_DoubleAttr_X)<<endl;
			}

		}
		else if (status == GRB_INF_OR_UNBD) {
			cout << "The model cannot be solved because it is infeasible or unbounded" << endl;
		}
		else if(status == GRB_INFEASIBLE) {
			cout << "The model cannot be solved because it is infeasible" << endl;
		}
		else if(status == GRB_UNBOUNDED) {
			cout << "The model cannot be solved because it is unbounded" << endl;
		}
		else {
			cout << "Optimization was stopped with status" << status << endl;
		}


	} catch(GRBException e) {
		cout << "Error code = " << e.getErrorCode() << endl;
		cout << e.getMessage() << endl;

	} catch(...) {
		cout << "Exception during optimization" << endl;

	}

	getchar();
	return 1;
}