2018.9.29 练习

版权声明：Zhining https://blog.csdn.net/weixin_43214609/article/details/82903234

1. 选择排序

int main()
{
	int arr[] = { 3,6,5,23,4,2,7,8 };
	int i, j, p = 0;
    int len = sizeof(arr) / sizeof(arr[0]) ;

	for (i = 0; i < len - 1; i++)
	{
		int min = arr[i];
		for (j = i + 1; j < len ; j++)
		{
		
			if (arr[j] < min)
			{
				p = min;  min = arr[j];  arr[j] = p;
			}
		}
	 arr[i] = min;
	}
		printf("排序之后的数组是：\n");
		for (i = 0; i < len; i++)
		{
			printf("%d ", arr[i]);
		}
	system("pause");
	return 0;
}

结果如图：

2. 冒泡排序

//从左向右冒泡
 
int main()
{
	int arr[] = { 2,5,3,1,6,7,4,3,9,0 };
	int len = sizeof(arr) / sizeof(arr[0]);
	int i = 0, j = 0, p = 0;

	for (i = 0; i < len-1; i++ )   //扫描len-1次
	{
		for (j = 0; j < len-1-i; j++)   //每次比较的起点不同
		{
			if (arr[j] > arr[j + 1])   //比较相邻两个数
			{
				p = arr[j];   arr[j] = arr[j + 1];   arr[j + 1] = p;
			}

		}

	}

	printf("排序之后的数组是：\n");
	for (i = 0; i < len; i++)
	{
		printf("%d ", arr[i]);
	}

	system("pause");
	return 0;
}

//从右向左冒泡

int main()
{
	int arr[] = { 2,5,3,1,6,7,4,3,9,0 };
	int len = sizeof(arr) / sizeof(arr[0]);
	int i = 0, j = 0, p = 0;

	for (i = len-1; i >= 0; i--)   //扫描len-1次
	{
		for (j = len - 1 - i; j >= 0; j--)   //每次比较的起点不同
		{
			if (arr[j] < arr[j - 1])   //比较相邻两个数
			{
				p = arr[j];   arr[j] = arr[j - 1];   arr[j - 1] = p;
			}

		}

	}

	printf("排序之后的数组是：\n");
	for (i = 0; i < len; i++)
	{
		printf("%d ", arr[i]);
	}

	system("pause");
	return 0;
}

结果如图：

3. 用指针实现strcmp函数功能

int my_strcmp(char *a, char *b);

int main()
{
	char str1[] = "visual";
	char str2[] = "studio";
	char *p1 = str1, *p2 = str2;

	printf("%d", my_strcmp(str1, str2));
	system("pause");
	return 0;
}

int my_strcmp(char *a, char *b)
{
	while (*a != '\0' && *b != '\0')
	{
		int ret = *a - *b;
		if (0 == ret)
		{
			*a++; *b++;
		}
		else
		{
			return ret;
			break;
		}
		return ret;
	}