6-1 交换两个整数的值

void fun(int* a, int* b)
{
	int* tmp = *a;
	*a = *b;
	*b = tmp;
}

6-2 利用指针找最大值

void findmax(int* px, int* py, int* pmax)
{
    *pmax = *px > *py ? *px : *py;
}

6-3 字符串的连接

char* str_cat(char* s, char* t)
{
    strcat(s, t);
    return s;
}

6-4 移动字母

void Shift(char s[])
{
    char ch[3];
    int count = 0;
    for (int i = 0; i < 3; i++)//存储前三个字符
    {
        ch[i] = s[i];
    }

    for (int i = 0; i < strlen(s) - 3; i++)//将后面的字符往前挪动覆盖
    {
        s[i] = s[i+3];
        count++;
    }

    for (int i = count,j=0; i < MAXS,j<3; i++,j++)//将存储的前三个字符存储到s数组的后面
    {
        s[i] = ch[j];
    }
}