/* Copyright 2025, Gurobi Optimization, LLC *//* Solve the classic diet model, showing how to add constraints   to an existing model. */usingSystem;usingGurobi;classdiet_cs{staticvoidMain(){try{// Nutrition guidelines, based on// USDA Dietary Guidelines for Americans, 2005// http://www.health.gov/DietaryGuidelines/dga2005/string[]Categories=newstring[]{"calories","protein","fat","sodium"};intnCategories=Categories.Length;double[]minNutrition=newdouble[]{1800,91,0,0};double[]maxNutrition=newdouble[]{2200,GRB.INFINITY,65,1779};// Set of foodsstring[]Foods=newstring[]{"hamburger","chicken","hot dog","fries","macaroni","pizza","salad","milk","ice cream"};intnFoods=Foods.Length;double[]cost=newdouble[]{2.49,2.89,1.50,1.89,2.09,1.99,2.49,0.89,1.59};// Nutrition values for the foodsdouble[,]nutritionValues=newdouble[,]{{410,24,26,730},// hamburger{420,32,10,1190},// chicken{560,20,32,1800},// hot dog{380,4,19,270},// fries{320,12,10,930},// macaroni{320,15,12,820},// pizza{320,31,12,1230},// salad{100,8,2.5,125},// milk{330,8,10,180}// ice cream};// ModelGRBEnvenv=newGRBEnv();GRBModelmodel=newGRBModel(env);model.ModelName="diet";// Create decision variables for the nutrition information,// which we limit via boundsGRBVar[]nutrition=newGRBVar[nCategories];for(inti=0;i<nCategories;++i){nutrition[i]=model.AddVar(minNutrition[i],maxNutrition[i],0,GRB.CONTINUOUS,Categories[i]);}// Create decision variables for the foods to buy//// Note: For each decision variable we add the objective coefficient//       with the creation of the variable.GRBVar[]buy=newGRBVar[nFoods];for(intj=0;j<nFoods;++j){buy[j]=model.AddVar(0,GRB.INFINITY,cost[j],GRB.CONTINUOUS,Foods[j]);}// The objective is to minimize the costs//// Note: The objective coefficients are set during the creation of//       the decision variables above.model.ModelSense=GRB.MINIMIZE;// Nutrition constraintsfor(inti=0;i<nCategories;++i){GRBLinExprntot=0.0;for(intj=0;j<nFoods;++j)ntot.AddTerm(nutritionValues[j,i],buy[j]);model.AddConstr(ntot==nutrition[i],Categories[i]);}// Solvemodel.Optimize();PrintSolution(model,buy,nutrition);Console.WriteLine("\nAdding constraint: at most 6 servings of dairy");model.AddConstr(buy[7]+buy[8]<=6.0,"limit_dairy");// Solvemodel.Optimize();PrintSolution(model,buy,nutrition);// Dispose of model and envmodel.Dispose();env.Dispose();}catch(GRBExceptione){Console.WriteLine("Error code: "+e.ErrorCode+". "+e.Message);}}privatestaticvoidPrintSolution(GRBModelmodel,GRBVar[]buy,GRBVar[]nutrition){if(model.Status==GRB.Status.OPTIMAL){Console.WriteLine("\nCost: "+model.ObjVal);Console.WriteLine("\nBuy:");for(intj=0;j<buy.Length;++j){if(buy[j].X>0.0001){Console.WriteLine(buy[j].VarName+" "+buy[j].X);}}Console.WriteLine("\nNutrition:");for(inti=0;i<nutrition.Length;++i){Console.WriteLine(nutrition[i].VarName+" "+nutrition[i].X);}}else{Console.WriteLine("No solution");}}}