Type Casting and Type Coercion

• If we perform an assignment from one type of data to another it has to be converted to the new type.
• If we allow the compiler to do this for us it is called coercion
• If we do it ourselves it it called conversion or type casting, or just perofrming a cast.
• It is best if we ALLWAYS do it ourselves.

           int a;
  	 float x;
  
  	 a = 7;
  	 x = a; // coercion
  	 x = float(a);        // conversion c++ style
  	 x = (float) a;       // conversion c style
      

• There are times where if we let the compiler do things for us we get unexpected results.
• When floats are converted to integers, the fractional part is simply dropped.

            int x;
  	  x = 2.999999;
  	  cout << x <<
  
  	  Will produce
  	  2
  	  (Plus a warning about assignment from double to int)
      

• int (floatValue + 0.5) will round if we need it.

Promotion

• When the compiler encounters an expression of mixed types (3+4.23) it promotes the int to a float and performs the operation, returning a float.
• This is probably best done with a cast.

          int totalPrograms = 4,
  	    studentCount = 6;
  	float averagePrograms;
  
  	averagePrograms = totalPrograms/studentCount;
  	averagePrograms = float(totalPrograms)/float(studentCount);