如何将这些for语句更改为嵌套while语句？

Question

i'm trying to change the nested for-loop into a nested while-loop. I've tried a few different ways but each time i try i cannot get the expected result which is: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

Try This:

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

See inline comments below:

    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); 

OUPUT

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

Answer 3

In general, to turn

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

Into a while loop, you move the initialization before it, put the condition in the while as it's condition, and put the increment (or other change step) inside the loop at the end.

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

The same logic should work for your inner loop as well.

Answer 4

All the initialisation statements are put before starting block of the while-loop and all the incremental/updation statements are executed just at the bottom where the loop has it's closing block placed! SO, just shift initialisations before the loop-body and push the incremental/decremental operations just before exiting the loop...

The answer after conversion would be :-

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++;
        }