Member Avatar for poloblue

Good Afternoon,

How do you write a two nested do-while loops to display the pattern:
*
**
***
****
*****
******

So far I have this code, but it just displays ******

int i=0;
    do{

        cout<<'*';
        i++;
    }while(i<5);
    cout<<endl;
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  • Latest Post Latest Post by poloblue

Dani AI

Generated

Brief clarification and a compact do-while answer that matches the original request. 's single loop printed ****** because it repeated a single print across one row; an inner loop is required to vary the number of asterisks per row. 's high-level point about outer/inner loops, 's pseudocode, and 's note to reinitialize the inner counter are all correct—reinitializing the inner counter inside the outer loop is the key.

int rows = 6;
int i = 1;
do {
    int j = 1;                      // reset inner counter each row
    do {
        std::cout << '*';
        j++;
    } while (j <= i);               // prints i asterisks on this row
    std::cout << '\n';
    i++;
} while (i <= rows);

Notes and troubleshooting tips: start both counters consistently (here at 1) so <= is natural; if starting at 0 use < instead. Because do..while executes the body at least once, guard with if (rows > 0) or use while when zero rows must produce no output. Common mistakes are initializing the inner counter outside the outer loop (causes increasing runs instead of per-row resets) or off-by-one logic in the inner condition. Using '\n' is preferable to std::endl unless an explicit flush is needed. This provides a minimal, correct do-while implementation while following the earlier advice from the thread.

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Member Avatar for Dani

You need two loops: An outer loop to keep track of the rows, and an inner loop to keep track of the number of asterisks per row.

Right now, you have an outer loop that is keeping track of the rows. But you need to replace that cout line with an inner loop to not just print one asterisk, but to loop through printing a variable number of asterisks.

Member Avatar for Lucaci Andrew

I will hant it in pseudocode, it's not too hard to figure it out by yourself:

i<-0;
while i != given_input_number do
    j<-0
    while j != i do
        print *
        increment(j)
    end_while
    print new line
    increment(i)
end_while

as cscgal said you have only the outer loop, so you need to put another loop, to count how many times you have to print the asterix. In this case, at each row, you'll have to print a number of asterixes which is greater than the one before, so a while till j != i suits this matter.

Edited by Lucaci Andrew
Member Avatar for poloblue

Lucaci Andrew,

I implemented this code, but it didn't work correctly.

int i = 0;
    int j = 0;

    while (i != 5)
    {
        do {

            while (j != i)
                do{
                cout<<'*';
                j++;
        }while(j<-0);
            cout<<endl;
            i++;
    }while(i<-0);
    }

Please tell me what I'm doing wrong. I would really appreciated your help.
Thank you

Member Avatar for zeroliken
  1. follow exactly the pseudocode to get your porgram to work (you only need 2 loops)
  2. I suggest you use only while loops
  3. include the j=0 at the start of your first loop as the counter for the number of asterisks you need to print every time
Member Avatar for Lucaci Andrew

poloblue I see you have 3 loops, from which 2 of them are do.... while loops. In my pseudocode I put only 2 while loops. As zeroliken said, follow the pseudocode and remember to initialize j=0 inside the first loop, so that after it prints 1 row of asterixes, to start again from 0 on the other row.

Member Avatar for poloblue

Lucaci Andrew, zeroliken, and Dani,

I made it to work with two nested while loops, I think that it can't de done using two nested while loops. Thanks everyone for your help.

Thank you

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