Introduction: Queue in C
Operation Queue
Here will be explained a little about the implementation of the Queue with Premtive ( Priority ) .
Without further ado immediately wrote to code themselves :
First type in the code below , and save it as interface.h :
#include
#include
#define Error(Str) FatalError(Str)
#define FatalError(Str) fprintf(stderr, "%s\n", Str), exit(1)
Then save the file queue.h code below :
#ifndef _Queue_h
#define _Queue_h
typedef int ElementType;
struct QueueRecord;
typedef struct QueueRecord *Queue;
Queue CreateQueue(int MaxElements);
void Enqueue(ElementType X, Queue Q);
ElementType Front(Queue Q);
void Dequeue(Queue Q);
void Preemptive(ElementType X, Queue Q);
void DisposeQueue(Queue Q);
void MakeEmpty(Queue Q);
int IsEmpty(Queue Q);
int IsFull(Queue Q);
#endif
Then type the code below and save the file as an implementation with queue.c :
#include "queue.h"
#include "fatal.h"
#include
struct QueueRecord{
int Capacity;
int Front;
int Rear;
int Size;
ElementType *Array;
};
static int Succ(int value, Queue Q);
void Enqueue(ElementType X, Queue Q){
if(IsFull(Q))
Error("Full Queue");
else{
Q->Size++;
Q->Array[Q->Rear]=X;
Q->Rear = Succ(Q->Rear,Q);
}
}
Queue CreateQueue(int MaxElements){
Queue Q = NULL;
Q=malloc(sizeof(struct QueueRecord));
if(Q==NULL)
FatalError("Out of Space!!!");
Q->Array=malloc(sizeof(ElementType) * MaxElements);
if(Q->Array==NULL)
FatalError("Out of space!!!");
Q->Capacity=MaxElements;
MakeEmpty(Q);
return Q;
}
void Preemptive(ElementType X, Queue Q){
if(IsFull(Q))
Error("Full Queue");
else{
Q->Size++;
Q->Array[Q->Front]=X;
Q->Rear = Succ(Q->Rear,Q);
}
}
ElementType Front(Queue Q){
if(!IsEmpty(Q))
return Q->Array[Q->Front];
Error("Empty Queue");
return 0;
}
void Dequeue(Queue Q){
if(IsEmpty(Q))
Error("Empty queue");
else{
Q->Size--;
Q->Front = Succ(Q->Front, Q);
}
}
void DisposeQueue(Queue Q){
if(Q != NULL ){
free(Q->Array);
free(Q);
}
}
static int Succ(int Value, Queue Q){
if(++Value == Q->Capacity)
Value=0;
return Value;
}
void MakeEmpty(Queue Q){
Q->Size = 0;
Q->Front = 0;
Q->Rear = 0;
}
int IsEmpty(Queue Q){
return Q->Size == 0;
}
int IsFull(Queue Q){
return Q->Size == Q->Capacity;
}
Save the file with the name fourth klien.c that functions as a client
#include
#include "queue.h"
int main(){
Queue Q;
int i;
int n=20;
static int max_queue_size = 20;
Q = CreateQueue(max_queue_size);
Preemptive(90,Q);
printf("%d\t",Front(Q));
Dequeue(Q);
for(i=0;i
for(i=0;i
if(Q!=NULL){
if(i%2==0){
Enqueue(i,Q);
}
}
if(i%2==0)
printf("%d,",i);
}
}
DisposeQueue(Q);
return 0;
}
Once compiled it will display results from the sum of the even numbers in a row from the start of 0 to 18 .Results of the sum is number 90 .Number is the series are :
90 0,2,4,6,8,10,12,14,16,18.
