我试图找到我要求用户输入的 3 个分数的平均值

Question

我试图理解为什么我输入了 scores1、scores2 和 scores3
被当作​​一个字符串。例如：score1 = 1，score2 = 1，score3= 1。平均得分 计算为 111/3 而不是 3/3..

  player1 = prompt(" Welcome Player 1! Please Enter your name ");
  alert(" Hello, " + player1+".");


  p1score1 = prompt(' Enter first score. ');
  p1score2 = prompt(' Enter second score. ');
  p1score3 = prompt(' Enter third score. ');

  /*p1score1 = 89;
  p1score2 = 120;
  p1score3 = 103;
  */

  p1avgScore = (p1score1 + p1score2 + p1score3)/3;

  console.log(" Congratulations " + player1 + ". Your scores are: " + 
  p1score1 + ", " + p1score2 + ", " + p1score3 + ".");
  console.log(" Your average score of all three games are: " + 
  p1avgScore);

---

Answer 1

这是因为prompt() 函数returns a string，而不是导致(p1score1 + p1score2 + p1score3) 产生字符串p1score1、p1score2 和p1score3 的串联的数字，而不是执行算术运算（即加法) 的总和。

考虑通过添加parseFloat() 进行以下调整以解决此问题：

p1score1 = parseFloat( prompt(' Enter first score. ') );
p1score2 = parseFloat( prompt(' Enter second score. ') );
p1score3 = parseFloat( prompt(' Enter third score. ') );

通过这样做，每个prompt() 的结果被解析为一个数字，这意味着p1score1 等的值类型是number。现在这意味着将在这一行上执行加法，而不是字符串连接：

(p1score1 + p1score2 + p1score3)/3

希望有帮助！

var player1 = prompt(" Welcome Player 1! Please Enter your name ");
alert(" Hello, " + player1 + ".");


var p1score1 = parseFloat(prompt(' Enter first score. '));
var p1score2 = parseFloat(prompt(' Enter second score. '));
var p1score3 = parseFloat(prompt(' Enter third score. '));

var p1avgScore = (p1score1 + p1score2 + p1score3) / 3;

console.log(" Congratulations " + player1 + ". Your scores are: " +
  p1score1 + ", " + p1score2 + ", " + p1score3 + ".");
console.log(" Your average score of all three games are: " +
  p1avgScore);

Answer 2

您只需要以整数/浮点数解析您的输入。

player1 = prompt(" Welcome Player 1! Please Enter your name ");
  alert(" Hello, " + player1+".");


  p1score1 = parseInt(prompt(' Enter first score. '));
  p1score2 = parseInt(prompt(' Enter second score. '));
  p1score3 = parseInt(prompt(' Enter third score. '));

  /*p1score1 = 89;
  p1score2 = 120;
  p1score3 = 103;
  */

  p1avgScore = (p1score1 + p1score2 + p1score3)/3;

  console.log(" Congratulations " + player1 + ". Your scores are: " + 
  p1score1 + ", " + p1score2 + ", " + p1score3 + ".");
  console.log(" Your average score of all three games are: " + 
  p1avgScore);