C++, getting gibberish from const unisgned char array

November 14, 2022

I am trying to write a program with a simple login interface for school in C++. I am new and still learning but I am getting a strange error with the following snippet of code. Inside the loop it outputs the username,password and name just as intended but if I try to access the array later it outputs gibberish. Any help with this is greatly appreciated:

EDIT: Thanks everyone! You suggestions helped to fix the problem. I needed to use strdup, It is not a standard c function but is really easy to implement, just run a google search!

sql = "SELECT username,password,real_name from Users"; 

const  unsigned char* usernames[20]; // 20 max usernames
const  unsigned char* passwords[20];
const  unsigned char* names[20];
rc =    sqlite3_prepare_v2(db, sql, -1, &stmt, NULL);     //sqlite3_exec(db, sql, callback, usernames, &zErrMsg);


if( rc != SQLITE_OK ) {
      printf("error: %s ", sqlite3_errmsg(db));
   return 1;
   } 
   
   int i  = 0;
   while ((rc = sqlite3_step(stmt)) == SQLITE_ROW) {
     
    usernames[i]= sqlite3_column_text (stmt, 0);
    passwords[i] = sqlite3_column_text(stmt, 1);
    names[i] = sqlite3_column_text(stmt, 2);
 //Prints fine
   cout << usernames[i] << ":" << passwords[i] << ":" << names[i] << "\n"; 
    i = i + 1 ;
}

//Prints gibberish
cout << usernames[0];