Numeric Data Types

• Integers
  • numbers without a decimal point (or decimal point to the extreme right)
  • short, int , long
  • signed, unsigned

    short SmallNumber;
    int NormalNumber;
    long BigNumber;
    unsigned int NormalPositiveNumber;
           

  • Literals
    • {+|-} digit*
    • No commas.
    • if it starts with a 0 it is in octal.
    • if it starts with a 0x it is in hex.
  • Sizes vary among machines.
  • Integers that are too large, or too small (-) produce overflow.
  • A warning is something that the compiler finds that is wrong, but it will continue to produce code.
  • Warnings are not acceptable in your programs
• Floating Point
  • These are real numbers (with a decimal point in the number)
  • float, double, long double
  • Sizes vary based on machine
  • litterals
    • {+|-}{digit*}{.}{digit*}{E{+|-}digit*}
    • 1.234565
    • 1.0E5
    • 1.0E-5
  • Floating point numbers are limited in size.
    • Consider 1/3 in decimal = .3333333333333...
    • .1 in base 2 is .000101001010010100...
• Declaring constants and variables
  • Just like before
  • const int MAXSTUDENTS = 10;
  • const int PI = 3.14159265;
  • int x;
  • float temprature;
• Assignment Statements
  • x = 5;
  • temprature = 33.94;
• Simple Expressions
  • + : add two numbers
  • - : subtract
  • These are either unary or binary

  • 
    int a,b,c;
    a = 3;
    b  = -a;
    c = +b; // really does nothing
    a = b - c;
    c = b + a;
           

  • * : multiply
  • / : divide
    • With integers, we need to be careful
    • a = 4/5; // a will be 0
    • We are not allowed to divide by 0
      • May produce floating point exception
  • % : integer remainder
    • 6%2 = 0 (2*3 = 6)
    • 13%3 = 1 (4*3+1 = 13)
• Two more strange operators
  • auto increment and auto decrement
  • prefix and postfix
  • a = a + 1
  • a++
  • ++a
• Rules of precedence
  • From Left to right, at the same level
  • Unary +,-
  • * / %
  • + -
  • When in doubt use ()
• Conversion, Type Casting
  • You tell it to change

  • int a;
    float b;
    char c;
    
    b = float(a);  // c++ style
    b = (float) a;  // c style
    a = int(b);
    a = (int) b;
    a = int (c);
          

• Coercion
  • Letting the compiler do it for you.

  • int a;
    float b;
    char c;
    
    b = a;  
    a = b;
    a = c;
          

• You should type cast or convert your variables
• In eather case, floats are truncated, not rounded.
• IntValue = int (FloatValue + 0.5); // this will round

The two example programs from class.

• example1.C
• example2.C

Problem: Write a program that will turn a measurement in inches to Miles, yards, feet and inches

Unit	conversion
1 Mile	63360 inches
1 Yard	36 inches
1 Foot	12 inches