C objective something wrong with if statement : <p><a href="https://i.stack.imgur.com/yGidv.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/yGidv.png" alt="the code"></a></p>

<p><strong>This code written in c objective with Visual Studio</strong></p>

<p>Today a friend of mine sent this code. In university they tried to make a grade calculation program. <strong>The problem is when you write -0 to input and press enter it gives result as the last if statement regardless the if statement is.</strong></p>

<p>Same conclusion appears when you write +0 etc.
Why this is happening any ideas? Thanks in advance.</p>
