5. Expressions

• 
  // compute an area of a rectangle:
  int length = 20; // the simplest expression: a literal (here, 20)
                   // (here used to initialize a variable)
  int width = 40;
  int area = length*width;        // a multiplication
  int average = (length+width)/2; // addition and division   
  
  

• The usual rules of precedence apply:

  
     a*b+c/d    means    (a*b)+(c/d)    and not    a*(b+c)/d.
  
  

• If in doubt, parenthesize. If complicated, parenthesize.

• Don't write absurdly complicated expressions:

  
     a*b+c/d*(e-f/g)/h+7      // too complicated
  
  

• Choose meaningful names!