assignment to ‘char’ from ‘char *’ makes integer from pointer without a cast

Question

I implemented queue in my code and I'm doing polling in my code. It's giving warning there. "assignment to ‘char’ from ‘char *’ makes integer from pointer without a cast". Can anybody let me suggest where I'm mistaken.

#define QUEUE_SIZE 200
char buffer[100];
char queue[100] ; // queue implementaion 
char Rear = - 1;
char Front = - 1;

/*enqueue start */
  printf("3. code reached here \n");
   if (buffer != NULL)
   {
      if (Rear == QUEUE_SIZE - 1)
          printf("Overflow \n");
    else
    {
        if (Front == - 1)
        Front = 0;
        Rear = Rear + 1;
        queue[Rear] = buffer; // this line having above warning //

Answer 1

The type of queue[Rear] is a char and the type of buffer is char [100]. If you want to copy the first element it would be:

queue[Rear] = *queue;

If you want to you copy a range you would use memcpy(). As queue and buffer are the same size you have to be mindful about buffer overflow:

memcpy(&queue[Rear], buffer, sizeof queue - Rear);