c - 获取一系列已排序的小写字母

Question

该算法可以很好地处理整数，但自从我将它们转换为字符后，它一直在输出中打印 null:

/* sort a series of lower case letters using quicksort algorithm. */ 
#include <stdio.h>

#define N 10

// since c gets the ascii code when returning an int for a char variable.

char quicksort(char a[], char low, char high);
char split(char a[], char low, char high);
int a[N];

int main(void)
{
    int i;

    printf("Enter  letters to be sorted: ");
    for (i = 0; i < N; i++)
        scanf("%d", &a[i]);
    quicksort(a, 0, N - 1);

    printf("In sorted order: ");
    for (i = 0; i < N; i++)
        printf("%s ", a[i]);
    printf("\n");

    return 0;
}
char quicksort(char a[], char low, char high)
{
    int middle;

    if (low >= high) return;
    middle = split(a, low, high);
    quicksort(a, low, middle - 1);
    quicksort(a, middle + 1, high);
}
char split(char a[], char low, char high)
{
    char part_element = a[low];

    for (;;) {
        while (low < high && part_element <= a[high])
            high--;
        if (low >= high) break;
        a[low++] = a[high];

        while (low < high && a[low] <= part_element)
            low++;
        if (low >= high) break;
        a[high--] = a[low];
    }

    a[high] = part_element;
    return high;
}

Answer 1

三个问题:

1. a 被声明为 int 数组，但所有函数都处理 char 数组。这意味着它们将无法正确迭代数组。将其更改为char a[N]。
2. 要读取字符，请使用 %c 格式说明符 scanf。
3. 要打印字符，请使用 %c 格式说明符 printf。