Use a std::deque. Push front until 5 are received then push front and pop back for every message after that. You can use al_draw_text to draw the text.

I would use a char array and strcpy():

#define MAX_MESSAGE_LENGTH 128

char messages[MAX_MESSAGE_LENGTH][5];
for (int i=0;i<5;i++) messages[0][i]='\n';

if (newmessagereceived())
{
   for (int i=0;i<4;i++) strcpy(messages[0][i],messages[0][i+1]);
   strcpy(messages[0][4],newmessagetext());
}

Don't initialize the first character to newline, initialize it to zero...

You don't need a deque, as Frank Drebin showed clearly. A deque is just a concept. It doesn't matter if its C++ or C, it's a container, and you can implement containers in any language you wish.

Frank implemented an array of 5 string buffers. When you get a new message, you move them all 'up' one and overwrite the first. Pretty simple, but effective.

Also, the array dimensions are reversed. It should be an array of 5 MAX_LENGTH buffers, not MAX_LENGTH buffers of size 5...

thank you everyone

attachment file(1234.mp4) is the test screen