JavaScript學習筆記（二）——函式和陣列

未名w發表於2019-02-02
JavaScript筆記函式陣列

第二章 函式簡介

1 第一個函式示例

 

 1 <script language="JavaScript" type="text/JavaScript">
 2 
 3 function bark(name,weight)
 4 
 5 {
 6 
 7 if(weight>20)
 8 
 9 console.log(name+" says WOOF WOOF");
10 
11 else
12 
13 console.log(name+" says woof woof");
14 
15 }
16 
17 bark("rover",23);
18 
19 bark("spot",18);
20 
21 </script>

 

2 函式引數錯誤處理

傳入引數不夠，將沒有相應引數實參的形參設定成未定義

如果傳遞的引數太多，js將忽略多餘的引數

如果無return返回undefined

第三章 陣列

1 第一個示例

 1 var score=[];
 2 
 3 var myarray=new Array(3);
 4 
 5 myarray[1]="asdf";
 6 
 7 scores=[60,50,60,58,54,52];
 8 
 9 var solution2=scores[2];
10 
11 var Length=scores.length;
12 
13 alert("There are "+Length+"solutions and Solution 2 produced "+solution2+" bubbles."+"and "+myarray[1]+"!");

 

2 第二個示例：

  1 <!doctype html>
  2 
  3 <html lang="en">
  4 
  5 <head>
  6 
  7 <title>Battleship</title>
  8 
  9 <meta charset="utf-8">
 10 
 11 </head>
 12 
 13 <body>
 14 
 15 <script language="JavaScript" type="text/JavaScript">
 16 
 17 var scores=[60,50,60,58,54,54,
 18 
 19 58,50,52,54,48,69,
 20 
 21 34,55,51,52,44,51,
 22 
 23 69,64,66,55,52,61,
 24 
 25 46,31,57,52,44,18,
 26 
 27 41,53,55,61,51,44];
 28 
 29 var highscore=printAndGetHighScore(scores);
 30 
 31 console.log("Bubbles test: "+scores.length);
 32 
 33 console.log(" Hightest Bubble score: "+highscore);
 34 
 35 var bestSolutions=[];
 36 
 37 bestSolutions=getBestResults(scores,highscore);
 38 
 39 console.log("Solution with the hightest score: "+bestSolutions);
 40 
 41 function printAndGetHighScore(scores)
 42 
 43 {
 44 
 45 var highscore=0;
 46 
 47 var output;
 48 
 49 for(var i=0;i<scores.length;i++)
 50 
 51 {
 52 
 53 output="Bubble solutoin #"+i+" score: "+scores[i];
 54 
 55 console.log(output);
 56 
 57 if(scores[i]>highscore)
 58 
 59 highscore=scores[i];
 60 
 61 }
 62 
 63 return highscore;
 64 
 65 }
 66 
 67 function getBestResults(scores,highscore)
 68 
 69 {
 70 
 71 var bestSolutions=[];
 72 
 73 //var j=0;
 74 
 75 for(var i=0;i<scores.length;i++)
 76 
 77 {
 78 
 79 if(scores[i]==highscore)
 80 
 81 {
 82 
 83 //bestSolutions[j]=i;
 84 
 85 //j++;
 86 
 87 bestSolutions.push(i);
 88 
 89 }
 90 
 91 }
 92 
 93 return bestSolutions;
 94 
 95 }
 96 
 97 </script>
 98 
 99 </body>
100 
101 </html>

 

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