dynamic name in function cvSaveImage

Question

i have code to input image name like IMG01.

 ostringstream input;
    input << z << ".jpg";
    string filename = input.str();
    const char* filename1 = filename.c_str(); [image processing here...]

then, i want save an image result with name bwIMG01.jpg using cvSaveImage. Exp:

cvSaveImage("bwIMG01.jpg", imgBW);

my problem is to write change the output name for every image. i've tried this code below, but it is not work....

char savedImg [30];
string savedCode = "bw";
savedImg = savedCode+filename;
cvSaveImage(savedImg, imgBiner);

any idea?

Answer 1

Change it to:

cvSaveImage(string(savedCode+filename).c_str(), imgBiner);

Suggestion: since you're using C++, you should use the new C++ API instead, it will work directly:

imwrite(savedCode+filename, imgBiner);

Answer 2

please use the c++ api, and the handy cv::format() instead:

cv::Mat imBW;
for ( int i=0; i<30; i++ )
    imwrite( format("bwIMG%02d.jpg", i), imgBW);

again, please avoid the old c-api, it is no more developed.