C++ 在一个小型玩具项目中实现终端历史记录功能

按照要求，下面是如何在代码中实现堆栈解决方案. 我没有发现 struct 构件front, rear, view的用处，但我将它们完好无损地留在了 struct 中.也许我添加的全局变量stack_top替换了其中一个或两个 struct 成员的意图？

我不喜欢全局变量，但堆栈指针(stack_top)需要由两个函数共享，所以我们就在这里.如果全球赛太可怕了，你当然可以用不同的方式进行编码.它当然可以被添加为GT_SCQueue的成员，这是一个简单的修改，对吗？

经过测试、可运行的代码如下:https://godbolt.org/z/bfr4bfr5o

#include<stdio.h>
#include<stdlib.h>
#include<string.h>


#define GT_SCQUEUE_SIZE 1000

/* Only one modification to the structure ... */
typedef struct {
    char *buffer[GT_SCQUEUE_SIZE]; /* ... here. */
    int front;  /* unused */
    int rear;   /* unused */
    int view;   /* unused */
} GT_SCQueue;


GT_SCQueue scq = {{0}, -1, -1, 0};
int stack_top = -1;

/*---------------------------------------------------------------------------------------------
    GT_SCQueue_Push()

    Places the item in param string onto the stack.
*---------------------------------------------------------------------------------------------*/
int GT_SCQueue_Push(GT_SCQueue* scq, const char* string) 
{
    if(stack_top < GT_SCQUEUE_SIZE-1)
    {
        stack_top++;
    }
    else 
    {
        printf("Stack Overflow items: %d  Max: %d .... moving 1st item out of stack.\n", stack_top+1, GT_SCQUEUE_SIZE);
        return 0;
    }
    /*Add new item on the right */
    scq->buffer[stack_top] = strdup(string);

    if(!scq->buffer[stack_top])
    {
        printf("GT_SCQueue_Push() memory error!\n");
        return 0;
    }
    printf("GT_SCQueue_Push() added element [%s].  Elements on the stack: %d  Available: %d\n", 
            string, stack_top+1, GT_SCQUEUE_SIZE-(stack_top+1) );

    /* Return success */
    return 1;
}


/*---------------------------------------------------------------------------------------------
    GT_SCQueue_Pop()

    Pops an item off the stack and into param string.
*---------------------------------------------------------------------------------------------*/
int GT_SCQueue_Pop(GT_SCQueue* scq, char *string) 
{
    if(stack_top < 0)
    {
        printf("UNDO Stack Underflow -- index: %d", stack_top);
        return 0;
    }
    strcpy(string, scq->buffer[stack_top] );
    free(scq->buffer[stack_top]);
    scq->buffer[stack_top] = NULL;
    printf("GT_SCQueue_Pop() popped element index: %d of string [%s]\n", stack_top, string);
    stack_top--;
    return 1;
}

int main() 
{
char b1[20];

    GT_SCQueue_Push(&scq, "Hello You!");
    GT_SCQueue_Pop(&scq, b1);
    printf("Report from main() -- Popped [%s]\n", b1);
}

输出:

    T_SCQueue_Push() added element [Hello You!].  Elements on the stack: 1  Available: 999
    GT_SCQueue_Pop() popped element index: 0 of string [Hello You!]
    Report from main() -- Popped [Hello You!]