com1 由于线程退出或应用程序请求，已放弃 I/O 操作

#include <iostream.h>
void myfunction();
int x=5,y=7;
void main()
{
cout<<"x from main:"<<x<<"\n";
cout<<"y from main:"<<y<<"\n";
myfunction();
cout<<"back from myfunction!\n\n";
cout<<"x from main:"<<x<<"\n";
cout<<"y from main:"<<y<<"\n";//换行是"\n",双引号括起来,上面类似
return;//main函数修饰符是void,无返回值
}
void myfunction()
{
int y=10;
cout<<"x from myfuncion:"<<x<<"\n";
cout<<"vy from myfunction:"<<y<<"\n";//双引号没匹配，成对出现
}

close串口不就行了本回答被网友采纳