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POarray in circular queue not getting initialised
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copied!<p>I am having problem in the c implementation of circular queue. The enqueue operation is not working properly. The value is not getting initialised in the array.</p> <p>the structure for queue is:</p> <pre><code>typedef struct { int a[5]; int tail; int head; int cap; }Que; </code></pre> <p>the enqueue function:</p> <pre><code> int enque(Que *q,int num) { if((q->head)==(q->tail )) return -1; if(q->head==-1) q->head=0; q->a[q->tail]=num; (q->tail) ++; if(q->tail ==q->cap) q->tail=0; return 0; } </code></pre> <p>the dequeue function:</p> <pre><code> int deque(Que *q) { if((q->head)==-1) return -1; int b= q->a[q->head]; (q->head)++; if(q->head==q->cap) q->head=0; if(q->head==q->tail) q->head=-1; return b; } </code></pre> <p>the head is position of the index to be dequeued and tail is the index where the element has to be added. The initial values of head is -1 , tail is 0 and cap is 5. These values have been set by another function.</p> <p>@Klas Lindbäck Here is the complete code:</p> <pre><code>#include <stdlib.h> #include <stdio.h> typedef struct { int a[5]; int tail; int head; int cap; }Que; int deque(Que *q) { if((q->head)==-1) return -1; int b= q->a[q->head]; (q->head)++; if(q->head==q->cap) q->head=0; if(q->head==q->tail) q->head=-1; return b; } void initialize(Que *q) { q->head=-1; q->tail=0; q->cap=5; } int enque(Que *q,int num) { if((q->head)==(q->tail )) return -1; if(q->head==-1) q->head=0; q->a[q->tail]=num; printf("%d \n",q->a[q->tail]); (q->tail) ++; if(q->tail ==q->cap) q->tail=0; return 0; } int main() { Que q; initialize(&q); int i=1; for(;i<=5;i++) { int num; printf("input a number: "); scanf("%d",num); enque(&q,num); } int c=q.a[0]; printf("%d %d %d\n",q.a[2],c,q.a[3]); } </code></pre>

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