使用选择排序对数组进行排序

Question

#include<stdio.h>
#include <time.h>

int selectionSort(int data[], int count)
{
  int a,b;
  int tmp;
  int minimum;
  for(a=0; a<count-1;a++){
  minimum = a;
    for(b=a+1;b<count;b++){
          if(data[minimum]>data[b]) {
            minimum = b;
            }
        }
        tmp = data[a];
        data[a]=data[minimum];
        data[minimum]=tmp;
}
  return 0;
}


int main(){
    int randomarray[10];
    int i;
    int k;
    srand(time(NULL));
    for(i=1; i<=10; i++){
    randomarray[i]=rand()%100;
    selectionSort(randomarray[i], k = 10 );
     printf("%d\n",randomarray[i]);

  }
return 0;

}

我正在尝试创建一个对随机整数数组进行排序的程序。我认为我的函数声明有问题，但我不习惯使用C。错误如下：

semihosting_example.c:13:5: warning: implicit declaration of function 'srand' [-Wimplicit-function-declaration]
semihosting_example.c:15:5: warning: implicit declaration of function 'rand' [-Wimplicit-function-declaration]
semihosting_example.c:16:5: warning: passing argument 1 of 'selectionSort' from incompatible pointer type [enabled by default]
semihosting_example.c:6:6: note: expected 'int *' but argument is of type 'int (*)[10]'ing_example.c:6:6: note: expected 'int *' but argument is of type 'int (*)[10]

Answer 1

下面是更新后的代码，其中包含适当的标头。我正在尝试创建一个包含数组的函数，该函数调用包含数组的函数：

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

int selectionSort(int (*)[10], int count)
{
  int a,b;
  int tmp;
  int minimum;
  for(a=0; a<count-1;a++){
  minimum = a;
    for(b=a+1;b<count;b++){
          if(data[minimum]>data[b]) {
            minimum = b;
            }
        }
        tmp = data[a];
        data[a]=data[minimum];
        data[minimum]=tmp;
}
  return 0;
}


int main(){
    int randomarray[10];
    int i;
    int k;
    srand(time(NULL));
    for(i=1; i<=10; i++){
    randomarray[i]=rand()%100;
    selectionSort(randomarray[i], k = 10 );
     printf("%d\n",randomarray[i]);

  }
return 0;

}

Answer 2

这是你的程序的修订版：

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

static void selectionSort(int data[], int count)
{
    for (int a = 0; a < count - 1; a++)
    {
        int minimum = a;
        for (int b = a + 1; b < count; b++)
        {
            if (data[minimum] > data[b])
                minimum = b;
        }
        int tmp = data[a];
        data[a] = data[minimum];
        data[minimum] = tmp;
    }
}

int main(void)
{
    int randomarray[10];

    srand(time(NULL));
    for (int i = 0; i < 10; i++)
        randomarray[i] = rand() % 100;

    printf("Before:\n");
    for (int i = 0; i < 10; i++)
        printf("%d: %d\n", i, randomarray[i]);
    selectionSort(randomarray, 10);
    printf("After:\n");
    for (int i = 0; i < 10; i++)
        printf("%d: %d\n", i, randomarray[i]);
    return 0;
}

运行时，它会生成如下输出：

Before:
0: 73
1: 63
2: 73
3: 80
4: 28
5: 19
6: 63
7: 96
8: 82
9: 46
After:
0: 19
1: 28
2: 46
3: 63
4: 63
5: 73
6: 73
7: 80
8: 82
9: 96

请注意，它在排序前和排序后都会打印数组，这样您就可以判断排序是否正确。

代码不使用k；它尽可能晚地声明变量。

如果替换该行：

selectionSort(randomarray, 10);

通过以下方式：

selectionSort(&randomarray, 10);

您将看到以下错误消息：

$ gcc -O3 -g -std=c11 -Wall -Wextra -Werror -Wmissing-prototypes -Wstrict-prototypes \
>     sort53.c -o sort53 
sort53.c: In function ‘main’:
sort53.c:32:19: error: passing argument 1 of ‘selectionSort’ from incompatible pointer type [-Werror=incompatible-pointer-types]
   32 |     selectionSort(&randomarray, 10);
      |                   ^~~~~~~~~~~~
      |                   |
      |                   int (*)[10]
sort53.c:5:31: note: expected ‘int *’ but argument is of type ‘int (*)[10]’
    5 | static void selectionSort(int data[], int count)
      |                           ~~~~^~~~~~
$

这来自于GCC 10.1.0，但它与问题中发布的错误消息非常相似。如果您将调用替换为：

selectionSort(randomarray[0], 10);

则错误消息为：

sort53.c: In function ‘main’:
sort53.c:32:30: error: passing argument 1 of ‘selectionSort’ makes pointer from integer without a cast [-Werror=int-conversion]
   32 |     selectionSort(randomarray[0], 10);
      |                   ~~~~~~~~~~~^~~
      |                              |
      |                              int
sort53.c:5:31: note: expected ‘int *’ but argument is of type ‘int’
    5 | static void selectionSort(int data[], int count)
      |                           ~~~~^~~~~~
cc1: all warnings being treated as errors