如何將這些for語句更改為嵌套while語句？

Question

我正在嘗試將嵌套的for循環更改為嵌套的while循環。 我嘗試了幾種不同的方法，但是每次嘗試都無法獲得預期的結果，即：T = 1 T = 1 T = 2 T = 4 T = 5 T = 11 R = 30

  public static void main(String[] args) { int s = 0; int t = 1; //first for-loop i'm trying to make a while-loop for (int i = 0; i < 5; i++) { s = s + i; //second for-loop i'm trying to make a while-loop for (int j = i; j > 0; j--) { t = t + (j-1); } s = s + t; System.out.println("T is " + t); } System.out.println("S is " + s); } 

Answer 1

嘗試這個：

public static void main(String[] args)
    {
        int s = 0;
        int t = 1;
        int i=0;
        //first for-loop i'm trying to make a while-loop
           while(i<5)
         {
            s = s + i;
            int j=i;
            //second for-loop i'm trying to make a while-loop
            while(j>0)
            {
               t = t + (j-1);
               j--;
            }
            s = s + t;
            System.out.println("T is " + t);
            i++;
        }
        System.out.println("S is " + s);


}

Answer 2

請參閱下面的內聯評論：

    int s = 0;
    int t = 1;
    int i = 0; // init i outside the while-loop
    while (i < 5) // replaces for-loop stop condition
    {
        s = s + i;
        int j = i; // init j outside the while-loop
        while (j > 0) // replaces for-loop stop condition
        {
            t = t + (j-1);
            j--; // decrement j
        }
        s = s + t;
        System.out.println("T is " + t);
        i++; // increment i
    }
    System.out.println("S is " + s); 

輸出

T is 1
T is 1
T is 2
T is 5
T is 11
S is 30

Answer 3

一般來說，轉

for (int i = 0; i < 5; i++) {
    // stuff goes here
}

進入while循環，您將初始化移到它的前面，將條件放入while作為條件，最后將增量（或其他更改步驟）放入循環內。

int i = 0;
while (i < 5) {
    // stuff goes here
    i++;
}

同樣的邏輯也應適用於您的內部循環。

Answer 4

所有初始化語句都放在while循環的開始塊之前，而所有增量/更新語句都在循環將其結束塊放置的底部執行！ 所以，只需在循環體之前移動初始化並在退出循環之前推送增量/減量操作...

轉換后的答案將是：

int i=0;
while(i<5)
         {
            s = s + i;
            //second for-loop i'm trying to make a while-loop
            int j=i;  
            while(j>0)
            {
               t = t + (j-1);
               j--;
            }
            s = s + t;
            System.out.println("T is " + t);
            i++;
        }