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1. How to calculate the execution time of an instruction x=3*a? (Don’t write code to find out)
gettimeofday()
/*
需要的头文件： <sys/time.h>
int gettimeofday(struct timeval *tv,struct timezone *tz);
strut timeval {
long tv_sec; /* 秒数 */
long tv_usec; /* 微秒数 */
};
*/
#include <sys/time.h>
void function(void); /* your function */
int main(void)
{
struct timeval fun_start,fun_end;
gettimeofday(&fun_start,NULL);
function();
gettimeofday(&fun_end,NULL);
return 0;
}
/*
需要的头文件： <sys/time.h>
int gettimeofday(struct timeval *tv,struct timezone *tz);
strut timeval {
long tv_sec; /* 秒数 */
long tv_usec; /* 微秒数 */
};
*/
#include <sys/time.h>
void function(void); /* your function */
int main(void)
{
struct timeval fun_start,fun_end;
gettimeofday(&fun_start,NULL);
function();
gettimeofday(&fun_end,NULL);
return 0;
}
一般都这样获得执行时间，但是不太精确，如果我想要精确可以利用CPU的运算周期来计算不过那个代码不哪么容易写的。
2. Write pseudo code to show your algorithm.
void Delete( Student* head, long number )
{
Student* p;
if(!head)
{
cout << "\nList Null!" << endl;
return;
}
if(head->number == number)
{
p = head;
head = head->next;
delete p;
return;
}
for(Student* pGuard = head; pGuard->next; pGuard = pGuard->next)
{
if(pGuard->next->number == number)
{
p = pGuard->next;
pGuard->next = p->next;
delete p;
cout << number << "has been deleted" << endl;
return;
}
}
cout << number << "is not found" << endl;
}
{
Student* p;
if(!head)
{
cout << "\nList Null!" << endl;
return;
}
if(head->number == number)
{
p = head;
head = head->next;
delete p;
return;
}
for(Student* pGuard = head; pGuard->next; pGuard = pGuard->next)
{
if(pGuard->next->number == number)
{
p = pGuard->next;
pGuard->next = p->next;
delete p;
cout << number << "has been deleted" << endl;
return;
}
}
cout << number << "is not found" << endl;
}
其实 现在现在几乎所有语言都hashtable的对象，一句话估计就搞定的，估计我这样些出来你们要说不正确。
3a. Ball and buttons: State machine table
|
State \ Event |
Click Play |
Click Pause |
Reach to the end |
|
Init |
消失 |
消失 |
可用 |
|
Play |
消失 |
可用 |
消失 |
|
Pause |
可用 |
消失 |
消失 |
3b. OO class design of “Ball and buttons”
a) How many classes? What are the names of classes?
2
Ball buttons
b) What are the key attributes and methods?
属性
Enabled
方法
Click()
c) Draw the uml class diagram. (bonus,选做题)
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删除 Guest (2008-10-07 15:41:37, 评分: 5 )