跪求大神出现，作业题不知道哪儿出毛病了

yangqi2008

task main()
{
int alfa, alfa0=180, b=8192, filehandle, N=100, time, begin_time=FirstTick();
float U=7.3;
string s;
DeleteFile("k10txt");
CreateFile("k10txt", b, filehandle);
while (true)
{
long x;
x=MotorRotationCount(OUT_A);
time = CurrentTick() - begin_time;
Nx=alfa0-alfa/180; OnFwd(OUT_A,N);
U=U/1000; N=Nx/U*1000;
if (abs(N)>100) N=sign(N)*100;
s = NumToStr(a) + NumToStr(time);
WriteLnString(filehandle,s,b );
Wait(6);
}
CloseFile(filehandle);
}
马达只转一下，这是为什么？