Parallelogram with 3 loops with c++ - c++

Question

Its my first year in computer science and I'm having some trouble with this problem.
The instructor asks to write a code for a parallelogram:
Enter number of rows: 13
*
**
***
****
*****
******
*******
******
*****
****
***
**
*
...with forced odd entry (like 4 changing to 5). rules are - I can't use stew - must draw shape using only 3 loops - plus one loop for forced entry (while r is between 3 and 23) - must use the total number of rows or current row for all calculations (can't use previous row and can't generate your own numbers)
int main() {
int control = 0;
int i = 0, j = 0, k = 0, l = 0;
int r = 0, c = 0, crntRow = 0, crntRow2 = 0,
cuur_8r = 0, space = 0, star = 0;
char a = '-', b = '+';
//cin >> r;
r = 11;
if (!(r % 2))
r++;
c = 0;
//cout << c << r;
for (i = 0; i < r; i++)
{
space = r / 2;
star = r / 2;
crntRow = i;
while (crntRow > space)
{
space++;
cout << a;
}
//cout << j;
for (int j = 0; j < c; j++)
{
if (star > j)
{
cout << b;
}
}
c++;
cout << '\n';
}
}
TLDR: this is the terrible code I came up with so far, I don't know how to shrink the number of stars after rows/2

Answer 1

The three loops that your instructor was referring to are:
An outer loop over the lines
A loop to prefix spaces to each line (0 spaces for the first half)
A loop to print stars on each line (this is always non-zero)
Here is a very stripped-down example:
int i, j, k, sp, st;
int r = 11;
// 1. An outer loop over the lines
for (i = 0; i < r; i++)
{
if(i <= r/2) {
sp = 0; // No spaces in the first half
st = i + 1; // Increasing stars in the first half
} else {
sp = i - r / 2; // Increasing spaces in the second half
st = r - i; // Decreasing stars in the second half
}
// 2. A loop to prefix spaces to each line (0 spaces for the first half)
for(j = 0; j < sp; j++) cout << ' ';
// 3. A loop to print stars on each line (this is always non-zero)
for(k = 0; k < st; k++) cout << '*';
cout << '\n';
}
As an excercise, you can do the same thing in two loops:
An outer loop over the lines
An inner loop over the character in each line
In this case, you would have to select which character to print during each iteration of the inner loop.