Problem with handling txt files in C++

Question

I am developing a C++ program that should read the keyboard data store them with hash, after performing the reading it must have in its main menu the save option.

I can read the save files using the hash and all.

The problem is at the time of creating the file, I would like to do a for that create the files with the default name, example

data_1
data_2
data_3
assim por diante

I made this code, but for some reason it creates only the file of zero index and as if I kept repeating the name and replacing the file 4 times that is the size of the defines TAM;

void func_arquivo::cria_arquivo(){
   ofstream arquivo;
    for(int i=0;i<TAM;i++){
        char nome[TAM];
        sprintf(nome, "Data-%d.txt",i);
        arquivo.open(nome, ios::app);
        arquivo.close();
    }
}

Answer 1

According to the function documentation sprintf:

The size of the buffer should be large enough to contain the entire Resulting string (see snprintf for a Safer version).

According to your comment the size of buffer is 4, you’re trying to save at least 10 characters...

You can increase the capacity of the buffer, for example char nome[FILENAME_MAX] or use the function snprintf, where the maximum number of bytes which will be written, thus:

char nome[FILENAME_MAX];
// ...
snprintf(nome, FILENAME_MAX, "Data_%d.txt", i);
// ....

See DEMO