tesseract-ocr API example in C++ of changing init parameters

/*
 * https://groups.google.com/d/msgid/tesseract-ocr/7dd534f7-3e85-480f-bb81-3d34c7af0c05%40googlegroups.com?utm_medium=email&utm_source=footer
 * Compile and run with:
 *
 * $ g++ -o init_para_example init_para_example.cpp -ltesseract -llept && ./init_para_example
 */

#include "leptonica/allheaders.h"
#include "tesseract/baseapi.h"
#include "tesseract/strngs.h"
#include "tesseract/genericvector.h"

int main(int argc, char **argv) {
    PIX  *pixs;
    char *outText;
    const char *filename = "/usr/src/tesseract-ocr.qmake/test/12OUT_2.jpg";
    const char *language = "ita";
    const char *datapath = "/usr/src/tesseract-ocr/";
    tesseract::PageSegMode pagesegmode = tesseract::PSM_AUTO;

    if (argv[1])
        filename = argv[1];

    if ((pixs = pixRead(filename)) == NULL) {
        printf("Unsupported image type of file %s.\n", filename);
        exit(3);
    }

    // turn of dictionaries -> only possible during init
    GenericVector<STRING> vars_vec;
    vars_vec.push_back("load_system_dawg");
    vars_vec.push_back("load_freq_dawg");
    vars_vec.push_back("load_punc_dawg");
    vars_vec.push_back("load_number_dawg");
    vars_vec.push_back("load_unambig_dawg");
    vars_vec.push_back("load_bigram_dawg");
    vars_vec.push_back("load_fixed_length_dawgs");
    //vars_vec.push_back("user_patterns_suffix");

    GenericVector<STRING> vars_values;
    vars_values.push_back("F");
    vars_values.push_back("F");
    vars_values.push_back("F");
    vars_values.push_back("F");
    vars_values.push_back("F");
    vars_values.push_back("F");
    vars_values.push_back("F");
    //vars_values.push_back("pharma-words");

    tesseract::TessBaseAPI *api = new tesseract::TessBaseAPI();
    printf("Using tesseract c++ API: %s\n", api->Version());

    api->Init(datapath, language, tesseract::OEM_DEFAULT,
              NULL, 0, &vars_vec, &vars_values, false);
    api->SetVariable("tessedit_char_whitelist",
                     "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
                     "0123456789,®");
    api->SetVariable("language_model_penalty_non_dict_word", "0");
    api->SetPageSegMode(pagesegmode);
    api->SetImage(pixs);

    // Check if change of init parameters was successful
    STRING var_value;
    api->GetVariableAsString("load_system_dawg", &var_value);
    printf("Variable 'load_system_dawg' is set to '%s'\n", var_value.string());

    outText = api->GetUTF8Text();
    printf("OCR output: \n%s", outText);

    api->End();
    delete [] outText;
    pixDestroy (&pixs);

    return 0;
}