如何使用'for loop‘代替'while loop’

Question

我不得不使用while、do-while和for循环为一个在线的pre java类编写以下程序。寻找一个小小的解释。提前感谢！

PS在寻找参考书时，这是Java还是Javascript？对于一本好的参考书有什么建议吗？我理解了这个概念，大部分情况下，魔鬼当然是在细节中。

public class ExamsFor {

    public static void main(String[] arguments) {


    int inputNumber; // One of the exams input by the user.
    int sum;     // The sum of the exams.
    int count;   // Number of exams.
    Double Avg;    // The average of the exams.


    /* Initialize the summation and counting variables. */

    sum = 0;
    count = 0;

    /* Read and process the user's input. */

    TextIO.put("Please enter the first exam: "); // get the first exam.


        inputNumber = TextIO.getlnInt();

    for (inputNumber!=0; sum += inputNubmer; count++ ) {  // had the while loop below enter here, worked

    TextIO.put("Please enter the next exam, or 0 to end: "); // get the next exam.  
    inputNumber = TextIO.getlnInt();
    } 

    /* Display the result. */

    if (count == 0) {
    TextIO.putln("You didn't enter any data!");
    }
    else {
    Avg = ((double)sum) / count;
    TextIO.putln();
    TextIO.putln("You entered " + count + " exams.");
    TextIO.putf("The average for the exams entered is %1.2f.\n", Avg);
    } 

    } // end main ()
}  // end class ExamsFor

/*  Had the following 'while loop' in place of the 'for loop'


while (inputNumber != 0) {
    sum += inputNumber;  // Add inputNumber to running sum.
    count ++;        // Count the input by adding 1 to the count.

*/

Answer 1

您的for循环不应该是：(请注意前面的内容；以及sum+=inputNumber中的拼写错误)

for (;inputNumber!=0; sum += inputNumber, count++ )

while循环应该是

while(inputNumber!=0) {
// rest of the things
 sum+=inputNumber;
 count++;
}

Answer 2

您可以比较for和while语句，观察到您在迭代构造中主要需要4件事：

condition (A)

• a条件中使用的值的初始值，用于检查是否保持迭代(B)

• a语句，该语句修改每次(C)

• the语句本身的正文时检查的值(BODY)

对于for，您有

for (A; B; C)
  BODY

而对于while (这里充满了文字笑话:)，您的代码如下

A;
while (B)
{
  BODY;
  C;
}

这很简单，不是吗？

Answer 3

阅读this并将您的for循环与预期的语法进行比较，看看哪里出了问题。