Originally posted by: Sara94

Hi
I am new in using concrete technology.I wrote a small program, this code works well if I use scanf, but if I read data from a file it does not work, I think its error is related to fscanf.
#include<stdio.h>
#include<math.h>
#include <stdlib.h>
#include<conio.h>
#include <ilcplex/ilocplex.h>

int e5,d,extra;
FILE* in;
ILOSTLBEGIN

int ple(int extra93){
IloEnv env;

IloModel model(env);

IloNumVar a( env, 3, 100, ILOINT);
IloNumVar b( env, 2, 100, ILOINT);
model.add(IloMinimize(env, 1*a+d*b));
model.add(a+b==6);

IloCplex cplex(model);
cplex.solve();

env.out() << "Cost:" << cplex.getObjValue() << endl;

env.end();

e5=0;
return(e5);
}
int main ()
{
in = fopen("in.txt", "r");
fscanf(in,"%d",&d);
extra=0;
ple(extra);

}
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

How does your file in.txt look like?
If you print out the value of 'd' after you read it, does it look as expected?
I also see that you are mixing C code (fopen, fscanf) into your C++ program. You may want to use C++ classes to do the same:

// Read integer from console:
#include <iostream>
int d;
std::cin >> d;
// Read integer from file:
#include <fstream>
int d;
std::ifstream in("in.txt");
in >> d;
in.close();

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#DecisionOptimization

Originally posted by: Sara94

Thanks for your help
my problem was solved, but I have a new problem. when i run the program, i face this error:

IBM ILOG CPLEX Optimization Studio TeamEAT Edition
This application has requested the runtime to terminate it in an unusual way.please contact the application's support team for more information.
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Originally posted by: SystemAdmin

I guess you are getting some sort of exception? You should catch that exception and print the error message, that will allow a better analysis of your problem.
To catch the exception and print its message rewrite your main() program to something like this:

int main(void)
{
   try {
      // your code here
      ...
      return 0;
   } catch (IloException& e) {
      std::cerr << "IloException: " << e << std::endl;
      return -1;
   } catch (...) {
      std::cerr << "Unknown exception!" << std::endl;
      return -1;
   }
}

Do you see any useful messages when you do that?

Maybe also have a look at the examples that come with CPLEX and illustrate how to write code that uses Concert C++.
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#DecisionOptimization

Originally posted by: Sara94

I wrote this code and the result is:

Concert exception caught: CPLEX Error 1217: No solution exists.
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#DecisionOptimization

Originally posted by: SystemAdmin

OK, then it is pretty clear what you are doing wrong: Your model has no solution but you are still trying to do

env.out() << "Cost:" << cplex.getObjValue() << endl;

This attempts to access the current solution but as there is no solution it throws an exception.
Note that function cplex.solve() returns true if a solution is available. So your code should look like this:

if ( cplex.solve() ) {
   // CPLEX found at least one feasible solution.
   // We can query that solution.
   env.out() << "Cost:" << cplex.getObjValue() << endl;
}
else {
   // No solution was found. The model is infeasible or
   // some sort of limit (time limit, node limit, ...)
   // expired before a feasible solution could be found.
   env.out() << "No feasible solution found." << endl;
}

Again, it might be helpful to go through the examples that come with CPLEX to learn about the different results with which a solve() may return and how to handle them.
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: Sara94

Thanks a lot for your help. my problems were solved.
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#DecisionOptimization