Useless use of array element in void context at ./t2 line 30 (#1)
    (W void) You did something without a side effect in a context that
+ does
    nothing with the return value, such as a statement that doesn't re
+turn a
    value from a block, or the left side of a scalar comma operator.  
+Very
    often this points not to stupidity on your part, but a failure of 
+Perl
    to parse your program the way you thought it would.  For example, 
+you'd
    get this if you mixed up your C precedence with Python precedence 
+and
    said
    
        $one, $two = 1, 2;
    
    when you meant to say
    
        ($one, $two) = (1, 2);
    
    Another common error is to use ordinary parentheses to construct a
+ list
    reference when you should be using square or curly brackets, for
    example, if you say
    
        $array = (1,2);
    
    when you should have said
    
        $array = [1,2];
    
    The square brackets explicitly turn a list value into a scalar val
+ue,
    while parentheses do not.  So when a parenthesized list is evaluat
+ed in
    a scalar context, the comma is treated like C's comma operator, wh
+ich
    throws away the left argument, which is not what you want.  See
    perlref for more on this.
    
    This warning will not be issued for numerical constants equal to 0
+ or 1
    since they are often used in statements like
    
        1 while sub_with_side_effects();
    
    String constants that would normally evaluate to 0 or 1 are warned
    about.
    
Missing argument in printf at ./t2 line 29, <IN> line 5 (#2)
    (W uninitialized) A printf-type format required more arguments tha
+n were
    supplied.
    
Use of uninitialized value in subtraction (-) at ./t2 line 38, <IN> li
+ne 5 (#3)
    (W uninitialized) An undefined value was used as if it were alread
+y
    defined.  It was interpreted as a "" or a 0, but maybe it was a mi
+stake.
    To suppress this warning assign a defined value to your variables.
    
    To help you figure out what was undefined, perl will try to tell y
+ou
    the name of the variable (if any) that was undefined.  In some cas
+es
    it cannot do this, so it also tells you what operation you used th
+e
    undefined value in.  Note, however, that perl optimizes your progr
+am
    anid the operation displayed in the warning may not necessarily ap
+pear
    literally in your program.  For example, "that $foo" is usually
    optimized into "that " . $foo, and the warning will refer to the
    concatenation (.) operator, even though there is no . in
    your program.
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