使用 c 将数组和指针复制到源的最后一个元素之后

Question

是否可以初始化 double 组，然后将内容复制到另一个数组中。该程序应使用使用指针表示法的函数来复制原始源数组。

我应该使用的函数调用示例是 copy_ptrs(复制、源和指向源最后一个元素之后的元素的指针。)

这是我的主要引用

int main() 
{
    int i, num; 
    double source[MAX];
    double target1[MAX];
    double target2[MAX];
    double target3[MAX];


    printf("\nEnter number of elements to be read into the array: ");
    scanf("%d", &num);

    printf("\nEnter the values below (press enter after each entry)\n");

    for (i = 0; i < num; i++) 
    {
            scanf("%lf", &source[i]);
    }

    copy_arr(target1, source, num);
    copy_ptr(target2, source, num);
    copy_ptrs(target3, source, source + num);//This is how I was instructed to call the function.


    printf("\n\nCopying Complete!\n");

    return 0;
}

这是我的简单复制指针符号函数

void copy_ptr(double target2[], double source[], int num)
{
    int i;
    double *p, *q;

    p = source;
    q = target2;

    for (i = 0; i < num; i++)
    {
            *q = *p;
        q++;
        p++;
    }

    printf("\n\n***The second function uses pointer notation to copy the elements***\n");
    printf("===================================================================\n");
    q = target2;

    for(i = 0; i < num; i++)
    {

        printf("\n              Pointer_Notation_Copy[%d] = %.2lf",i, *q++);
    }
}

这是另一个使用数组表示法复制源数组的函数

void copy_ptr(double target2[], double source[], int num)
{
    int i;
    double *p, *q;

    p = source;
    q = target2;

    for (i = 0; i < num; i++)
    {
            *q = *p;
        q++;
        p++;
    }

    printf("\n\n***The second function uses pointer notation to copy the elements***\n");
    printf("===================================================================\n");
    q = target2;

    for(i = 0; i < num; i++)
    {

        printf("\n              Pointer_Notation_Copy[%d] = %.2lf",i, *q++);
    }
}

当我尝试添加第三个函数来满足分配时，我卡住了。如何获取指向源最后一个元素之后的元素的指针？

void copy_ptrs(double target3[], double source[], int num)
{
    int i;
    double *p, *q;

    p = source;
    q = target3;

    for (i = 0; i < num; i++)
    {
            *q = *p;
        q++;
        p++;
    }

    printf("\n\n***The third function uses pointer notation to copy the elements + the number of elements read in?***\n");
    printf("===================================================================\n");
    q = target3;

    for(i = 0; i < num; i++)
    {

        printf("\n              Pointer_Notation_Copy[%d] = %.2lf",i, *q++);
    }
}

Answer 1

您的陈述:

copy_ptrs(copy, source, and a pointer to the element following the last element of the source.)

和代码:

void copy_ptr(double target2[], double source[], int num)

不匹配。

你来电

copy_ptrs(target3, source, source + num);

也不符合函数定义。

您可以将函数更改为:

void copy_ptr(double target2[], double* source, double* end)

使其与您的语句和函数调用相匹配。

然后，您必须将实现更改为:

void copy_ptr(double target[], double* source, double* end)
{
   int i = 0;
   int num = end - source;
   double* p = source;
   double* q = target;

   for ( ; p != end; ++p, ++q)
   {
      *q = *p;
   }

   printf("\n\n***The second function uses pointer notation to copy the elements***\n");
   printf("===================================================================\n");

   q = target;
   for ( i = 0; i < num; ++i, ++q )
   {
      printf("\n              Pointer_Notation_Copy[%d] = %.2lf", i, *q);
   }
}