Pianotehead wrote:No key signature, no time signature or it may be considered as C major key signature by default. By including this feature the user would be learning not only the chords, but how they look in sheet music and thereby increasing his or her sight reading abilities.
If you don't have the key signature, then you aren't learning much about how the chords look in sheet music. The key signature is highly determinative of what chords are likely to be used. The fact that the chords used have no accidentals in their basic forms and have the particular accidentals they do in their extended and altered forms is all important to understanding the music.
You might think it is convenient to see chords written out with the accidentals so you aren't having to refer to the key signature to figure out the pitches. I thought that for a long, long time. Now that I am studying music more seriously, and I thought I was pretty serious before, I have realized that you need to think in terms of a scale being used, not all the keys on the keyboard. Then you think of where a note or harmony fits within the scale.
If you are playing in a major diatonic scale, the most common scale (e.g. C Major scale = c d e f g a b), then your most likely chords are built on the first (root), the fourth, and the fifth. (In C Major, on C, F, and G.) The triads built on these notes using the notes of the major diatonic scale are all major triads. (c-e-g, f-a-c, and g-b-d) Regardless of the key signature, this relationship is always true. Your I, IV, and V chords (major chords built on notes 1, 4, and 5 of the scale) never have accidentals regardless of the key. So a C# Major chord (c#-e#-g#) looks just like a C Major chord (c-e-g) but the key signature tells you that the notes are a half step higher. Seeing a C# Major chord in the key of C Major would be unusual except as a passing chord, e.g. a C -> C# -> Dmin harmonic progression.
If you see a C chord (c-e-g), you need to instinctively know that it is a major chord if it is the I, IV, or V chord of the key (for a C chord that would be C Major, G Major, and F Major). C will be a minor chord if it is the ii, iii, or vi chord (Bb Major, Ab Major, and Eb Major). In those three scales, c and g are natural and e is flat. C will be a diminished chord when it is the VIIdim chord (Db major). In those 7 scales the C chords all look the same but their character--major, minor, or diminished--is determined by the key signature. A C chord does not occur naturally in the other keys (D, A, E, B, F#, and C#) because those scales have a C#. In those scales when you see the C chord notes you would be playing C# Major (c#-e#-g#) in C# Major or F# Major (I or V), C# minor (c#-e-g#) in B, A, or E (ii, iii, or vi), or C#dim (c#-e-g) in D Major (VIIdim). So what you see in the sheet music (c-e-g) can mean many different things depending on the key signature. It probably is fair to say that it is more important to learn to read the key signatures than the chords if you want to read sheet music fluently.
In other words, you want to get used to seeing chords in their natural key signature settings because that is what you need to be able to recognize at a glance to read sheet music.