Exploring bases through C++

Objectives

Notes

• Let's use some C++ tricks to try to get a deeper insight into binary.
• Log into prog1, we will need c++20 for one small bit.
• Given a number, can we print out the binary/hex/octal representation?
• cout tricks:
  • The stream modifiers, dec, hex, oct
    • cout << std::hex << number
  • These change the state of the stream.
  • It defaults to dec
  • So you will want to reset it to dec after you are done in one of the other formats.
  • see this reference.
  • Write a program function that prints out several numbers in hex, octal and decimal.
    • Use the number 1024+512+256+32 + 8 + 4 +1
• What are these hex and octal things?
• In c++20, changed is 23 is std::format
  • reference
  • This will act like printf
    • It takes a format string
    • And a value
    • And returns the value formatted according to the string.
  • We don't care about much of this now
  • But there is a binary specifier

  •  #include < format >
    ...
    cout <<  std::format("{:b}",number) << endl; 

• Add this to your program, print the number in binary
  • You will need to add -std=c++20 and be running on prog1
  • Does this match the previous output.
  • Prove it to me.
• That is nice but here are two other pieces of information you might want for the next exercise
  • & is the bitwise and
    • It will and each bit of the data.
    • For example 1011 1010 & 1001 0110 = 1001 0010
    • Write a program to compute and print this.
      • << for integers is the bitwise shift left operator.
        • 1 << 1 = 10 (or 2)
        • 101 << 2 = 10100
        • It is essentially a multiply by 2 operator.
        • 101 >> 1 = 10
        • This is the bitwise shift right, or divide by 2.
      • size_of(expr) and size_of(type)
        • reference.
        • Returns the size, in bytes of the operator.
    • Write a function that will use & and << to convert an integer type to the equivalent binary bit string.
    • With just a little thought, you can make this work with negative numbers too.