C language uses function pointer to implement array sorting

最近看C语言有点烦，无论是自学的数据结构还是学校的指针课程，看着头都大了。
学校在PTA安排了此题，提交了多次总是报错，今天重新整理一遍且不按题目编程提示来写，提交终于正确。
（其实是最后一个数字不能有空格，而题目没有说明白）
将此题记录一下，说不定某些小伙伴需要呢？
此题可能不是标准答案，仅作参考。

Enter 10 integers for sorting and output. Use a function pointer to write a general sorting function. If you enter 1, the program will sort data in ascending order; if you enter 2, the program will sort data in descending order.

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Input example 1:

Input data, separated by spaces.
Input sample 1:
2 3 4 9 10 8 7 6 5 1
1

Output sample 1: The
output format The data format is as follows, separated by a space.
Output sample 1:
1 2 3 4 5 6 7 8 9 10

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Input example 2:

2 3 4 9 10 8 7 6 5 1
2

Sample output 2:
10 9 8 7 6 5 4 3 2 1

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#include <stdio.h>

void sort_1(int a[], int n)
{
	int i, j, * p = a;
	for (i = 0; i < n - 1; i++)
	{
		for (j = i + 1; j < n; j++)
		{
			if (*(p + i) > * (p + j))	//升序
			{
				int t;
				t = *(p + i);
				*(p + i) = *(p + j);
				*(p + j) = t;
			}
		}
	}
}

void sort_2(int a[], int n)
{
	int i, j, * p = a;
	for (i = 0; i < n - 1; i++)
	{
		for (j = i + 1; j < n; j++)
		{
			if (*(p + i) < * (p + j))		//降序
			{
				int t;
				t = *(p + i);
				*(p + i) = *(p + j);
				*(p + j) = t;
			}
		}
	}
}

int main()
{
	int i, j, a[10];
	for (j = 0; j < 10; j++)
		scanf("%d", &a[j]);
	int flag;
	scanf("%d", &flag);
	switch (flag)
	{
	case 1:
		sort_1(a, 10);
		break;
	case 2:
		sort_2(a, 10);
			break;
	}
	printf("%d", *(a));
	for (i = 1; i < 10; i++)
		printf(" %d", *(a + i));
	return 0;
}