Write a C program to print the given triangular number pattern using for loop. How to print the given number pattern using loop in C programming. Logic to print the given number pattern using C program.

## Required knowledge

## Logic to print the given pattern

To get the logic of the pattern given above have a close look to the pattern for a minute. You can easily note following points about the pattern.

- The pattern contains N rows (where N is the total number of rows to be printed).
- Each row contains exactly i columns (where i is the current row number).
- Now, talking about the numbers printed. They are printed in a special order i.e. for each odd row numbers are printed in ascending order and for even rows they are printed in descending order.
- For odd row first column value start at total_numbers_printed + 1 (where total_numbers_printed is the total numbers printed till current row, column).
- For even row first column value start at total_numbers_printed + i.

Based on the above logic lets write down the code to print the pattern.

## Program to print the given pattern

```
/**
* C program to print the given number pattern
*/
#include <stdio.h>
int main()
{
int i, j, count, value, N;
printf("Enter rows: ");
scanf("%d", &N);
count = 0;
for(i=1; i<=N; i++)
{
// Starting value of column based on even or odd row.
value = (i & 1) ? (count + 1) : (count + i);
for(j=1; j<=i; j++)
{
printf("%-3d", value);
// Increment the value for odd rows
if(i & 1)
value++;
else
value--;
count++;
}
printf("\n");
}
return 0;
}
```

Output

Enter rows: 5 1 3 2 4 5 6 10 9 8 7 11 12 13 14 15

Happy coding 😉