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#javascript-processing-example-basic-math-operatorprecedence.htm / htm



  <!DOCTYPE html>
  <html><head>
  <script src="javascript-processing-example-processing.js"></script>
  <script src="javascript-processing-example-init.js"></script>
  <link rel="stylesheet" href="javascript-processing-example-style.css">
  </head><body><h1><a href="http://ejohn.org/blog/processingjs/">Processing.js</a></h1>
  <h2>OperatorPrecedence</h2>
  
  <p>by REAS <http: reas.com="">
  
  If you don't explicitly state the order in which
  an expression is evaluated, they are evaluated based
  on the operator precedence. For example, in the statement
  "4 + 28", the 2 will first be multiplied by 8 and then the result will
  be added to 4. This is because the "*" has a higher precedence
  than the "+". To avoid ambiguity in reading the program, 
  it is recommended that is statement is written as "4 + (28)".
  The order of evaluation can be controlled through placement of
  parenthesis in the code. A table of operator precedence follows below.</http:></p>
  
  <p><a href="http://processing.org/learning/basics/operatorprecedence.html"><b>Original Processing.org Example:</b> OperatorPrecedence</a><br>
  <script type="application/processing">
  // The highest precedence is at the top of the list and 
  // the lowest is at the bottom.
  // Multiplicative: * / %
  // Additive: + -
  // Relational: < > <= >=
  // Equality: == !=
  // Logical AND: &&
  // Logical OR: ||
  // Assignment: = += -= *= /= %=
  
  size(200, 200);
  background(51);
  noFill();
  stroke(51);
  
  stroke(204);
  for(int i=0; i< width-20; i+= 4) {
    // The 30 is added to 70 and then evaluated
    // if it is greater than the current value of "i"
    // For clarity, write as "if(i > (30 + 70)) {"
    if(i > 30 + 70) {
      line(i, 0, i, 50);
    }
  }
  
  stroke(255);
  // The 2 is multiplied by the 8 and the result is added to the 5
  // For clarity, write as "rect(5 + (2 * 8), 0, 90, 20);"
  rect(4 + 2 * 8, 52, 90, 48);
  rect((4 + 2) * 8, 100, 90, 49);
    
  stroke(153);
  for(int i=0; i< width; i+= 2) {
    // The relational statements are evaluated 
    // first, and then the logical AND statements and 
    // finally the logical OR. For clarity, write as:
    // "if(((i > 10) && (i < 50)) || ((i > 80) && (i < 160))) {"
    if(i > 20 && i < 50 || i > 100 && i < width-20) {
      line(i, 151, i, height-1);
    } 
  }
  </script><canvas width="200" height="200"></canvas></p>
  <div style="overflow: hidden; height: 0px; width: 0px;"></div>
  
  <pre><b>// All Examples Written by <a href="http://reas.com/">Casey Reas</a> and <a href="http://benfry.com/">Ben Fry</a>
  // unless otherwise stated.</b>
  // The highest precedence is at the top of the list and 
  // the lowest is at the bottom.
  // Multiplicative: * / %
  // Additive: + -
  // Relational: &lt; &gt; &lt;= &gt;=
  // Equality: == !=
  // Logical AND: &amp;&amp;
  // Logical OR: ||
  // Assignment: = += -= *= /= %=
  
  size(200, 200);
  background(51);
  noFill();
  stroke(51);
  
  stroke(204);
  for(int i=0; i&lt; width-20; i+= 4) {
    // The 30 is added to 70 and then evaluated
    // if it is greater than the current value of "i"
    // For clarity, write as "if(i &gt; (30 + 70)) {"
    if(i &gt; 30 + 70) {
      line(i, 0, i, 50);
    }
  }
  
  stroke(255);
  // The 2 is multiplied by the 8 and the result is added to the 5
  // For clarity, write as "rect(5 + (2 * 8), 0, 90, 20);"
  rect(4 + 2 * 8, 52, 90, 48);
  rect((4 + 2) * 8, 100, 90, 49);
    
  stroke(153);
  for(int i=0; i&lt; width; i+= 2) {
    // The relational statements are evaluated 
    // first, and then the logical AND statements and 
    // finally the logical OR. For clarity, write as:
    // "if(((i &gt; 10) &amp;&amp; (i &lt; 50)) || ((i &gt; 80) &amp;&amp; (i &lt; 160))) {"
    if(i &gt; 20 &amp;&amp; i &lt; 50 || i &gt; 100 &amp;&amp; i &lt; width-20) {
      line(i, 151, i, height-1);
    } 
  }</pre>
  </body></html>
[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

(C) Æliens 20/2/2008

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