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<html><head><title></title></head><body bgcolor=#ffffff> <a href="CodeConvTOC.doc.html">[Contents]</a> <a href="CodeConventions.doc4.html">[Prev]</a> <a href="CodeConventions.doc6.html">[Next]</a><hr><br> <a name="2991"> </a><h2 align="center">6 - Declarations</h2><a name="2992"> </a><h3> 6.1 Number Per Line</h3><p><a name="368"> </a>One declaration per line is recommended since it encourages commenting. In other words,</p><blockquote><pre>int level; // indentation levelint size; // size of table</pre></blockquote><p><a name="370"> </a>is preferred over</p><blockquote><pre>int level, size;</pre></blockquote><p><a name="614"> </a>Do not put different types on the same line. Example:</p><blockquote><pre><a name="15393"> </a> int foo, fooarray[]; //WRONG!</pre></blockquote></p><a name="1727"> </a><p><b>Note:</b> The examples above use one space between the type and the identifier. Another acceptable alternative is to use tabs, e.g.:<blockquote><pre>int level; // indentation levelint size; // size of tableObject currentEntry; // currently selected table entry</pre></blockquote><a name="18761"> </a><h3> 6.2 Initialization</h3><p><a name="18762"> </a>Try to initialize local variables where they're declared. The only reason not to initialize a variable where it's declared is if the initial value depends on some computation occurring first. </p><a name="16817"> </a><h3> 6.3 Placement</h3><p><a name="375"> </a>Put declarations only at the beginning of blocks. (A block is any code surrounded by curly braces "{" and "}".) Don't wait to declare variables until their first use; it can confuse the unwary programmer and hamper code portability within the scope. </p><blockquote><pre>void myMethod() { int int1 = 0; // beginning of method block if (condition) { int int2 = 0; // beginning of "if" block ... }}</blockquote></pre><p><a name="307"> </a>The one exception to the rule is indexes of <code>for</code> loops, which in Java can be declared in the <code>for</code> statement: </p><blockquote><pre>for (int i = 0; i < maxLoops; i++) { ... }</blockquote></pre><p><a name="377"> </a>Avoid local declarations that hide declarations at higher levels. For example, do not declare the same variable name in an inner block:</p><blockquote><pre>int count;...myMethod() { if (condition) { int count = 0; // AVOID! ... } ...}</pre></blockquote><a name="381"> </a><h3> 6.4 Class and Interface Declarations</h3><p><a name="207"> </a>When coding Java classes and interfaces, the following formatting rules should be followed: </p><ul><a name="390"> </a><li>No space between a method name and the parenthesis "(" starting its parameter list<a name="391"> </a><li>Open brace "{" appears at the end of the same line as the declaration statement<a name="394"> </a><li>Closing brace "}" starts a line by itself indented to match its corresponding opening statement, except when it is a null statement the "}" should appear immediately after the "{"</ul><blockquote><pre>class Sample extends Object { int ivar1; int ivar2; Sample(int i, int j) { ivar1 = i; ivar2 = j; } int emptyMethod() {} ...}</pre></blockquote><ul><a name="1733"> </a><li>Methods are separated by a blank line</ul><hr><br> <a href="CodeConvTOC.doc.html">[Contents]</a> <a href="CodeConventions.doc4.html">[Prev]</a> <a href="CodeConventions.doc6.html">[Next]</a> <hr><br><i><a href="Copyright.doc.html">Copyright</a> © 1995-1999, Sun Microsystems, Inc. All rightsreserved.</i><!-- Last updated: Thu Apr 15 09:03:50 1999 --></body></html>⌨️ 快捷键说明
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