So, the output should come out with a incrementing triangle of looped numbers (1,2,3,...) combined with a decrementing triangle of stars. Like this:

1********
12*******
123******
1234*****
12345****
123456***
1234567**
12345678*
123456789

So far I have this but just can't figure out how to decrement the stars.

#include <stdio.h>

int main()
{
    int i, j;
    for(i=1; i<=9; i  )
    {
        for (j=1; j<=i; j  )
        {
            printf ("%d",j);
        }

        int k;
        for(k=8; k>0; k--) {
            printf("*");
        }

        printf("\n");
    }
}

And it prints out this:

1*******
12*******
123*******
1234*******
12345*******
123456*******
1234567*******
12345678*******
123456789*******

CodePudding user response：

You have:

• For k in 8 down to 0 (exclusive),
  • Print *.

This always prints 8 stars, but you want 9-i of them.

• For k in i 1 to 9 (inclusive),
  • Print *.

CodePudding user response：

Note that all you need to do is subtract the amount of numbers printed per line from the expected (in this case) 9 expected characters. for(k=9 - i; k>0; k--)

#include <stdio.h>
int main()
{
    int i, j;
    for(i=1; i<=9; i  ){
        for (j=1; j<=i; j  ){
            printf ("%d",j);
        }
        int k;
        for(k=9 - i; k>0; k--) {
            printf("*");
        }
        printf("\n");
    }
}

Outputs:

1********
12*******
123******
1234*****
12345****
123456***
1234567**
12345678*
123456789

CodePudding user response：

printf has the built in ability to print only limited portions of a string.
That comes in EXTREMELY handy for problems like this:

#include <stdio.h>
int main(void) {
    int i=9;
    while(i --> 0)
    {
        printf("%.*s%.*s\n", 9-i, "123456789", i, "********");
    }
    return 0;
}

Output

1********
12*******
123******
1234*****
12345****
123456***
1234567**
12345678*
123456789

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