3.Print this pattern 

0000
000
00
0

Step 1: Define the number of rows

int rows = 4;

Step 2:Outer loop — controls rows

    for (int i = rows; i >= 1; i--) 

This loop runs from 4 down to 1.

Variable i tells us how many zeros to print on the current row.

When i=4, print 4 zeros; when i=3, print 3 zeros, and so on.

Step 3:Inner loop — prints zeros

  for (int j = 1; j <= i; j++) {

    printf("0");

 }

For each row, this loop prints zeros.

It runs i times, printing exactly i zeros in that row.

printf("0") prints zeros without moving to the next line.

Step 4:Move to the next line 

printf("\n");  //After printing zeros in the current row, this moves the cursor to the next line, so the next row prints below.