具有双*值的快速排序 [英] Quicksort with double* values

问题描述

我得到了一个用C编写的程序，该程序在具有int值的数组上实现Quicksort。我需要将其转换为将对具有double *值的数组执行Quicksort的程序。我以为我只需要将 int声明更改为 double *，但是由于某些原因，当我用非整数值测试数组时，该程序不再起作用。

I am given a programme in C which implements Quicksort on arrays with int values. I need to convert it into a programme which will implement Quicksort on arrays with double* values. I thought that I just need to change "int" declarations into "double*", but for some reason the programme no longer works when I test arrays with other values than integers.

有人可以帮忙吗？我真的对C语言编程一无所知，也不知道如何进行。这是 int程序：

Can someone please help? I really know almost nothing about programming in C and have no idea how to go on. Here is the "int" programme:

void quicksort(int a[], int n)
{
    if (n <= 1) return;
    int p = a[n/2];
    int b[n], c[n];
    int i, j = 0, k = 0;
    for (i=0; i < n; i++) {
        if (i == n/2) continue;
        if ( a[i] <= p) b[j++] = a[i];
        else            c[k++] = a[i];
    }
    quicksort(b,j);
    quicksort(c,k);
    for (i=0; i<j; i++) a[i] =b[i];
    a[j] = p;
    for (i= 0; i<k; i++) a[j+1+i] =c[i];
}


int main(void) {
    int i;
    /* das Array zum Sortieren */
    int test_array[] = { 5, 2, 7, 9, 6, 4, 3, 8, 1 };
    int N = sizeof(test_array)/sizeof(int);

    quicksort(test_array,  N);

    for(i = 0; i < N; i++)
        printf("%d ", test_array[i]);
    printf("\n");

    return 0;
}

推荐答案

当您替换 int 和 double 指针，则需要更改比较-比较指向的值，而不是指针本身。

When you replace the ints with double pointers, you need to change the comparisons - to compare the pointed to values, not the pointers themselves.

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