c++ 如何将字符转换为十六进制

Question

I know that when outputting hex I can use

cout<<hex<<(unsigned int)(unsigned char)ch<<endl 

but I am getting a character from standard input by using

cin.read((char*)&ch , sizeof(unsigned char))

how do I change ch to hex this time?

Answer 1

cin.read((char*)&ch , sizeof(unsigned char));
cout << hex << (unsigned int)(ch) << endl;

should work.

Answer 2

if you're trying to convert a single char to hex to do math with if for example, you can convert the ascii char representation to it's actual digit with a statement like:

char x = 'A';
int y = x;
if(y > 47 && y < 58)  //this covers 0-9
   y = y - 48;
else if (y > 64 && y < 71) // this covers A-F
   y = y - 55;

and use y as your new number. If you need to do it for more then one digit you can place this in a loop.