Automatically create several files in C or C++

We are working on algorithm development for voice recognition and are in process of analyzing various notes of test set. We have identified 30 voices. We will use them as our database. My straight question to the kind support group is, can I create the graphs directly using C program or C ++? We have good programmers in team. Presently they dump data into a text file. Then we manually copy paste them into excel and do the plotting activity. Your sincere help will improve our application. Next stage is to have dynamic database updating where this will be more necessary. Please teach.