C Program To Draw Pyramid of Stars, using For Loop

Lets write a C program to draw / print / display a pyramid / triangle formed from stars, using nested for loop.

Related Read:
Nested For Loop In C Programming Language
C Program To Draw Pyramid of Stars, using While Loop

Expected Output for the Input

User Input:
Enter no of rows of Pyramid
5

Output:

    
     *
    ***
   *****
  *******
 *********

Pyramid With 20 Rows

Video Tutorial: C Program To Draw Pyramid of Stars, using For Loop

Logic To Draw Pyramid of Stars, using For Loop

If num = 5;

First Iteration of outer for loop
row = 1;

1st inner for loop
condition:
num – row;
= 5 – 1
= 4
Four spaces gets printed.

2st inner for loop
condition:
2 * row – 1;
= 2 * 1 – 1;
= 2 – 1
= 1
One star gets printed.

Second Iteration of outer for loop
row = 2;

1st inner for loop
condition:
num – row;
= 5 – 2
= 3
Three spaces gets printed.

2st inner for loop
condition:
2 * row – 1;
= 2 * 2 – 1;
= 4 – 1
= 3
Three stars gets printed.

Third Iteration of outer for loop
row = 3;

1st inner for loop
condition:
num – row;
= 5 – 3
= 2
Two spaces gets printed.

2st inner for loop
condition:
2 * row – 1;
= 2 * 3 – 1;
= 6 – 1
= 5
Five stars gets printed.

Forth Iteration of outer for loop
row = 4;

1st inner for loop
condition:
num – row;
= 5 – 4
= 1
One space gets printed.

2st inner for loop
condition:
2 * row – 1;
= 2 * 4 – 1;
= 8 – 1
= 7
Seven stars gets printed.

Fifth Iteration of outer for loop
row = 5;

1st inner for loop
condition:
num – row;
= 5 – 5
= 0
Zero space gets printed.

2st inner for loop
condition:
2 * row – 1;
= 2 * 5 – 1;
= 10 – 1
= 9
Nine stars gets printed.

Source Code: C Program To Draw Pyramid of Stars, using For Loop

#include<stdio.h>

int main()
{
    int num, row, col, space;

    printf("Enter no of rows of Pyramid\n");
    scanf("%d", &num);

    for(row = 1; row <= num; row++)
    {
        for(space = 1; space <= (num-row); space++)
        {
            printf(" ");
        }
        for(col = 1; col <= (2*row-1); col++)
        {
            printf("*");
        }
        printf("\n");
    }

    return 0;
}

Output 1:
Enter no of rows of Pyramid
5

     *
    ***
   *****
  *******
 *********

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