iostream,ostrem,iostrem是类
cin,cout,ceer,clog是标准流对象
cout<<stu1.name<<' '<<stu1.id<<' '<<stu1.sex<<endl;
cin>>stu1.name>>stu1.id>>stu1.sex;
int num;
输出格式控制,hex十六进制,oct八进制,dec十进制
cout<<hex<<num<<' '<<dec<<num<<oct<<num;
(在c语言中,printf("%x %d %0",num,num,num);)