将字符串 student a am i或 ( I Am Prammer) 翻转为 i am a student或(Prammer Am I)

1.某公司2019秋招在线笔试题 ；联合体union

#include
#include
#include

union  var
{
     
	int a ;
	char m[5];
	int *p;
};
void test()
{
     
	printf("%d\n ",sizeof( union var));
}

int main()
{
     

	test();
	system("pause");
	return 0;
}

结果 ：8

2.字符翻转 将字符串 student a am i或 ( I Am Prammer) 翻转为 i am a student或(Prammer Am I)

#include
#include
#include
#include

void ReverseStringCode(char *start, char *end)//一小段字符翻转
	{
     
		assert(start);
		assert(end);

		while (start < end)
		{
     
			*start ^= *end;
			*end ^= *start;
			*start ^= *end;
			start++;
			end--;

		}


	}

	void ChangeString(char a[])//以空格划分，逐段翻转
	{
     

		//assert(a);

		char *p = a;
		char *prev = p;

		while (*p)
		{
     
			if (*p == ' ')
			{
     
				ReverseStringCode(prev, p - 1);
				p++;
				prev = p;

				continue;

			}

			p++;

		}
		ReverseStringCode(prev, p - 1);//翻转最后一个字符

		ReverseStringCode(a, p - 1);//整体翻转
	}



	void test01()//  将字符串  student a am i ( I Am   Prammer)  翻转为  i  am a     、、   student(Prammer   Am I)
	{
                                
		char a[] = " I Am Prammer";
		printf("before: %s\n", a);
		
		ChangeString(a);


		printf("after: %s\n", a);

		system("pause");

		return 0;

	}


int main()
{
     
	test01();

	system("pause");
	return 0;
}

结果 ：