Thread: [Help} Array of integers keeps returning value 2

Hi all, am currently doing a project from KNKing's C program a modern approach.

3 files involved. queueADT.h, queueADT.c, stackclient.c

code for queueADT.h

Code:

#ifndef QUEUE_H#define QUEUE_H


#include <stdbool.h>  /* C99+ only */


typedef int Item;
typedef struct queue_type *Queue;




Queue create(void);
void destroy(Queue s);
void insertend(Queue q, Item i);
void removebegin(Queue q);
Item returnfirst(Queue q);
Item returnlast(Queue q);
bool isempty(Queue q);


#endif

relevant code oif queueADT.c

Code:

 
//structure 
struct queue_type {
    Item queue[MAXQUEUESIZE];
    int firstemptyslot;
    int toberemoved;
    int numitems;
};

void insertend(Queue q,Item i)   //inserting number into the next slot in array
{
    if (q->numitems==100)
        queue_overflow();
    q->queue[q->firstemptyslot]= i;
    q->firstemptyslot++;
    q->numitems++;
    if (q->firstemptyslot>99)
        q->firstemptyslot=0;
}

Queue create(void)  //creating pointer to structure
{
  Queue q = malloc(sizeof(struct queue_type));
  if (q == NULL)
    terminate("Error in create: queue could not be created.");
  q->firstemptyslot = 0;
  q->toberemoved = 0;
  q->numitems = 0;
  return q;
}

Item returnfirst(Queue q){  //returning first number in the array
    if (isempty(q))
        queue_underflow();
    if (q->firstemptyslot == 0)
    return q->queue[q->toberemoved];


}

relevant code of stackclient.c (main). Basically I insert some numbers into the strcuture and get the program to print it back out

Code:

#include <stdio.h>
#include "queueADT.h"


int main(void)
{
  Queue s1, s2;
  Item n;


  s1 = create();
  s2 = create();


  insertend(s1, 4);
  insertend(s1, 8);






  printf("First number %d from s1\n", returnfirst(s1));
  removebegin(s1);
  //etc etc continue printing out numbers

The problem is that my program keeps giving out the number 2, or rather the function that returns a number from the structure in the array keeps returning the number 2, even though I inserted numbers such as 4 or 8 or other numbers.

I have spent quite some time changing things around but I cant figure out what is wrong. Would appreciate any kind help sirs thank you. Apologies if any of the code is formatted badly because I tried changing some code to fix it.

Originally Posted by laserlight

returnfirst appears to be incomplete: what do you return when the condition of the second if statement evaluates to false?

Hi sir that seems to have been causing the proble. Looks like i forgot to remove that line under return first lol .___.

Thank you!!!! Solved.