dec、hex、oct

cout利用控制符dec、hex、oct分别输出dec、hex、out进制，具体哪个是哪个你查查字典吧～

void (){

​    int a = 42;

​    cout<<"a = "<<a<<endl;

​		 cout<<hex; //十六进制

​	   cout<<"a = "<<a<<endl;

​	   cout<<oct; //八进制

​   	cout<<"a = "<<a<<endl;

}