la partie droite d'une contrainte doit etre constant (i.e. pas de variable)
Pour compiler
g++ -DIL_STD -I/opt/ibm/ILOG/CPLEX_Studio128/cplex/include -I/opt/ibm/ILOG/CPLEX_Studio128/concert/include -L/opt/ibm/ILOG/CPLEX_Studio128/cplex/lib/x86-64_linux/static_pic -L/opt/ibm/ILOG/CPLEX_Studio128/concert/lib/x86-64_linux/static_pic -o tuto tuto.cpp -lconcert -lilocplex -lcplex -lm -lpthread -ldl