I am trying to use cplex in eclipse in Ubuntu 12.04 but when I include ilocplex.h I get the following error
/opt/ibm/ILOG/CPLEX_Studio124/concert/include/ilconcert/ilosys.h:360:22: fatal error: iostream.h: No such file or directory
At the time ILOG's Concert library was first released, the older iostream.h headers were still common in C++ compilers, but it supports the standard iostream libraries. To use the standard headers and libraries, you need to define the IL_STD preprocessor symbol. Instructions for defining preprocessor directives in Eclipse/C++ can be found in this question.