二维数组

下午学习的二维数组，一维数组包含几个一维数组，包含一维数组的数组就变成了二维数组。

var arr = [1,2,3];//一维数组

var arr1 = [ [1,2,3], [1,2,3] ]; //二维数组

就像这样 [[77],[88],[99]];

打印三角形

var attr=[];
attr[0] = [" "," "," "," ","△"];
attr[1] = [" "," ","△","△","△"];
attr.push(["△","△","△","△","△"]);

console.log(attr);

for(var i = 0; i<attr.length;i++){
for(var j = 0; j<attr[i].length;j++){
document.write(attr[i][j]);
}
document.write("<br>");
}

接收三个学生的 三门成绩 保存为一个二维数组 计算每个学生的总分，平均分，班级的总分，每门课程成绩的平均分
function saveScore(){
var info = [ [], [], [] ];
var sum = 0;
var ke = [0,0,0];
for(var i = 0; i<info.length; i++){
info[i][0] = prompt("请输入学生姓名");
info[i][1] = prompt("请输入语文成绩");
info[i][2] = prompt("请输入数学成绩");
info[i][3] = prompt("请输入英语成绩");
info[i][4] = +info[i][1] + +info[i][2] + +info[i][3];
info[i][5] = info[i][4]/3;

sum = sum + +info[i][4]; //班级总成绩
ke[0] = ke[0] + +info[i][1];//语文总成绩
ke[1] = ke[1] + +info[i][2];//数学总成绩
ke[2] = ke[2] + +info[i][3];//英语总成绩

}
for(var i = 0; i<info.length;i++){
document.write(info[i][0]+"的语文成绩:" +info[i][1]+";数学成绩:" +info[i][2]+";英语成绩:" +info[i][3]+";总成绩:" +info[i][4]+";平均成绩:" +info[i][5]+"<br>")
}
document.write("班级总成绩:" +sum+"<br>")
document.write("语文平均成绩:" +ke[0]/3+";数学平均成绩:" +ke[1]/3+";英语平均成绩:" +ke[2]/3)

<input type="button" value="输入成绩" onClick="saveScore()">