使用每个计算用户输入的平均值答案

【问题标题】：Calculate average of user input using for each使用每个计算用户输入的平均值
【发布时间】：2014-09-20 18:23:02
【问题描述】：

您好，我是 Java 新手，正在尝试做一些练习来熟悉它。我正在尝试使用 for each 或增强的 for 循环来计算用户输入数字的总和和平均值。我所做的是将数字存储在一个数组中。你能检查我的代码是否正确。

Scanner scanner = new Scanner(System.in);

double inputNum;
double sum= 0;
int counter;

System.out.println("How many entries would you like input");
int entry = scanner.nextInt();

for (counter = 0; counter< entry; counter++){

    double [] numbers = new double[entry]; 
    System.out.println("Please input number " + (counter +1));
    numbers[counter] = scanner.nextDouble();

    for (double x : numbers[counter]) {
        x += sum;
    }

    System.out.println("The total sum is: " + sum);
    double average = sum/entry;
    System.out.println("The total average is: " + average);
}

【问题讨论】：

for-each 不适用于表达式类型double，需要使用数组或者一些Iterable
我正在检查是否可以使用 for each 循环

标签： java arrays for-loop

【解决方案1】：

您不需要内部循环。将每个输入存储在数组中后，您可以将其添加到总和中。

此外，您应该在外循环之外分配一次数组，而不是在每次迭代中。

double [] numbers = new double[entry];
for (counter = 0; counter< entry; counter++){       
    System.out.println("Please input number " + (counter +1));
    numbers[counter] = scanner.nextDouble();
    sum+= numbers[counter];
}
System.out.println("The total sum is: " + sum);
double average = sum/entry;
System.out.println("The total average is: " + average);

【讨论】：

但是不需要数组。只需跟踪总和。
@nmore 这也是正确的，但也许后面还有额外的代码需要数组。

【解决方案2】：

将求和和平均逻辑放在循环之外。这应该有效：

double [] numbers = new double[entry]; 
for (counter = 0; counter< entry; counter++){
  System.out.println("Please input number " + (counter +1));
  numbers[counter] = scanner.nextDouble();       
  sum += numbers[counter];
}

System.out.println("The total sum is: " + sum);
double average = sum/entry;
System.out.println("The total average is: " + average);

【讨论】：

【解决方案3】：

您不能将 for-each 与扫描仪一起使用。此外，您无需存储任何东西。只需跟踪总和即可。

Scanner scanner = new Scanner(System.in);

System.out.println("How many entries would you like input?");
int numEntries = scanner.nextInt();

double sum = 0;
for (counter = 1; counter <= numEntries; counter++) {
    System.out.println("Please input number " + counter + ": ");
    sum += scanner.nextDouble();
}
System.out.println("The total sum is: " + sum);
System.out.println("The average is: " + sum / numEntries);

【讨论】：

【解决方案4】：

相同的代码，循环外的平均值和无用的数组被删除：

Scanner scanner = new Scanner(System.in);

double sum = 0;

System.out.println("How many entries would you like input");
int entry = scanner.nextInt();

for (int counter = 1; counter <= entry; counter++) {
    System.out.println("Please input number " + counter);
    sum += scanner.nextDouble();
}

System.out.println("The total sum is: " + sum);
double average = sum / entry;
System.out.println("The total average is: " + average);

【讨论】：