在回圈佇列中如何檢查迭代器是否大于等于佇列的前元素-有解無憂

struct PCB
{
    int PID;
    int burstTime;
    int arrivalTime;
    int priorityScore;
    int startTime;
    int finishTime;
};

struct Queue
{
    int front;
    int rear;
    int length;       // Stores the maximum no. of processes that can be stored processes in the queue
    int size;         // Stores the current no. of processes in the queue
    struct PCB **arr; // Array of pointers storing the pointers to PCB. Storing "struct PCB*" type item in arr
};

void arrangeProcess(struct Queue *readyQ)
{
    if (isEmpty(readyQ))
    {
        printf("\nNo elements in Queue.\n");
        return;
    }

    int i = readyQ->front, temp = readyQ->size;
    int j, tempj;
    struct PCB *key;

    i = (i   1) % readyQ->length;

    while (i < temp)
    {
        key = readyQ->arr[i];
        j = (i   (readyQ->length) - 1) % readyQ->length; // Getting the previous element of i

        int lastIndex = (readyQ->front   readyQ->length - 1) % readyQ->length;

        // The while loop is executed if (j >= readyQ->front) and AT of arr[j] > AT of key
        while ((j != lastIndex) && ((readyQ->arr[j]->arrivalTime) > (key->arrivalTime))) 
        {
            tempj = (j   1) % readyQ->length; // Getting the next element of j

            readyQ->arr[tempj] = readyQ->arr[j];

            j = (j   (readyQ->length) - 1) % readyQ->length;
        }
        tempj = (j   1) % readyQ->length;
        readyQ->arr[tempj] = key;

        i = (i   1) % readyQ->length;
    }
}

這里的主要目的是根據到達時間對readyQ 中的PCB進行排序，我嘗試使用插入排序進行此操作，但是我找不到插入排序的內部回圈為佇列運行的合適條件，直到迭代器i大于等于readyQ的前面元素。如果readyQ已滿，即當readyQ 中存在最后一個元素時，我在程式中撰寫的條件將繼續回圈，否則它將完美運行。

請建議合適的回圈條件，以便即使在readyQ 中存在最后一個元素的情況下代碼也能完美運行

uj5u.com熱心網友回復：

不要使用實際的偏移量。根據撰寫回圈0..size-1，但實際上比較元素(front i) % length和(front j) % length

void arrangeProcess(struct Queue *readyQ)
{
    size_t num_eles = readyQ->size;
    if (!num_eles)
        return;

    size_t base_idx = readyQ->front;
    size_t max_eles = readyQ->length;

    for (size_t i=0; i<num_eles-1;   i) {
        size_t ii = ( base_idx   i ) % max_eles;
        struct PCB *a = readyQ->arr[ii];

        for (size_t j=i 1; j<num_eles;   j) {
            size_t jj = ( base_idx   j ) % max_eles;
            struct PCB *b = readyQ->arr[jj];

            ...
        }
    }
}

它更簡單，更不容易出錯。

轉載請註明出處，本文鏈接：https://www.uj5u.com/qiye/379870.html

標籤：C 指针队列插入排序循环队列

上一篇：我的代碼沒有在離線編譯器上正確輸出？

下一篇：使用指標的字符陣列未在C中更新