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copied!<p><code>i++</code> is an assignment to a variable <code>i</code>.</p> <p>In your case, <code>zero++</code> is an equivalent to <code>zero = zero + 1</code>. So <code>0++</code> would mean <code>0 = 0 + 1</code>, which makes no sense, as well as <code>getInt() = getInt() + 1</code>.</p> <p>More accurately :</p> <pre><code>int oneA = zero++; </code></pre> <p>means</p> <pre><code>int oneA = zero; zero = zero + 1; // OK, oneA == 0, zero == 1 </code></pre> <hr> <pre><code>int oneB = 0++; </code></pre> <p>means</p> <pre><code>int oneB = 0; 0 = 0 + 1; // wrong, can't assign value to a value. </code></pre> <hr> <pre><code>int oneC = getInt()++; </code></pre> <p>means</p> <pre><code>int oneC = getInt(); getInt() = getInt() + 1; // wrong, can't assign value to a method return value. </code></pre> <hr> <p>From a more general point of view, a variable is a <strong>L-value</strong>, meaning that it refers to a memory location, and can therefore be assigned. <strong>L</strong> in <strong>L</strong>-value stands for <strong>left</strong> side of the assignment operator (i.e. <code>=</code>), even if L-values can be found either on the left side or the right side of the assignment operator (<code>x = y</code> for instance).</p> <p>The opposite is <strong>R-value</strong> (<strong>R</strong> stands for <strong>right</strong> side of the assignment operator). R-values can be used only on the right side of assignment statements, to assign something to a L-value. Typically, R-values are literals (numbers, characters strings...) and methods.</p>

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