学科前沿技术（让用户来决定Windows任务管理器的CPU占用率）

题目：写一个程序，让用户来决定Windows任务管理器（Task Manager）的CPU占用率。程序越精简越好，计算机语言不限。例如，可以实现下面三种情况：

1. CPU的占用率固定在50%，为一条直线；

2. CPU的占用率为一条直线，但是具体占用率由命令行参数决定（参数范围1~ 100）；

3. CPU的占用率状态是一个正弦曲线。

 

完整代码如下：

#include<windows.h>
#include<cstdio>
#include<cmath>

constint PERIOD= 60* 1000;//60,000 ms
constint COUNT = 200;

constdouble PI = 3.1415926535898;
constdouble GAP= (double)PERIOD/ COUNT;
constdouble FACTOR= 2* PI / PERIOD;

typedefdouble Func(double);
inlineDWORD get_time() { returnGetTickCount(); }

doublecalc2(doublex) { return(1 +sin(FACTOR *x)) / 2;}

doublecalc3(double)
{
static doublecache[COUNT];
static intcount = 0;
static boolfirst = true;
if (first) {
doublex = 0.0;
for(int i = 0;i <COUNT; ++i,x +=GAP)
cache[i] =(1.0 +sin(FACTOR *x)) / 2.0;
first = false;
}
if (count >=COUNT) count = 0;
returncache[count++];
}

doublecalc4(double){ return0.8;}

voidsolve(Func *calc)
{
doubletb = 0;
while(1){
unsigned ta =get_time();
doubler =calc(tb);
if(r < 0|| r > 1)r = 1;
DWORD busy =r *GAP;
while(get_time()- ta < busy) {}
Sleep(GAP -busy);
tb +=GAP;
}
}


voidrun()
{
Func *func[]= {calc2, calc3, calc4 };
Func *calc= func[1];
const intMAX_CPUS = 32;
HANDLE handle[MAX_CPUS];
DWORD thread_id[MAX_CPUS];
SYSTEM_INFO info;
GetSystemInfo(&info);
const intnum =info.dwNumberOfProcessors;
for(int i = 0;i <num; ++i){
if( (handle[i] =CreateThread(NULL, 0,(LPTHREAD_START_ROUTINE)solve,
(VOID*)calc,0, &thread_id[i]))!= NULL)
SetThreadAffinityMask(handle[i], i +1);
}
WaitForSingleObject(handle[0],INFINITE);
}


intmain()
{
run();
}