Write a Program to Print the Following Pattern

Posted in

Vinay Khatri
Last updated on November 14, 2022

Problem Statement

We need to write a script in C, C++, and Python that can print the following pattern of Alphabets based on the user's entered letter.

Input

letter = F

Output

A
AB
ABC
ABCD
ABCDE
ABCDEF

Algorithm

• Ask the user to enter the height of the pattern h which ranges between 1 to 26 (A to Z).
• Create an outer loop i from range 1 to h .
• Inside the outer loop create a nested inner loop j range from 1 to i .
• Inside the inner loop, we will print the series of Alphabets using their ASCII code.
• The ASCII code for the Upper Case letter starts from 65.

C Program to Print a tringle of Alphabets.

#include <stdio.h>
int main()
{
int h, i, j;
char letter;
//ask user to input the height of the pattern
printf("Enter the height of pattern(1-26): ");
scanf("%d", &h);

for(i=1;i<=h;i++)
{
for(j=1;j<=i;j++)
{
//convert the integer ASCII code
//to equivalent character value
letter = j+64;

printf("%c",letter);
}

//print a new line after every row of alphabet series
printf("\n");
}

return 0;
}

Output

Enter the height of pattern(1-26): 5
A
AB
ABC
ABCD
ABCDE

C++ Program to Print a tringle of Alphabets

#include <ioistream>
using namespace std;

int main()
{
int h, i, j;
char letter;
//ask user to input the height of the pattern
cout<<"Enter the height of pattern(1-26): "; cin>>h;

for(i=1;i<=h;i++)
{
for(j=1;j<=i;j++)
{
//convert the integer ASCII code
//to equivalent character value
letter = j+64;

cout<<letter;
}

//print a new line after every row of alphabet series
cout<<endl;
}
return 0;
}

Output

Enter the height of pattern(1-26): 6
A
AB
ABC
ABCD
ABCDE
ABCDEF

Python Program to Print a tringle of Alphabets.

#ask user to input the height of the pattern
h = int(input("Enter the height of pattern(1-26): "))

#outer loop
for i in range(1,h+1):

for j in range(1, i+1):
# convert the integer ASCII code
# to equivalent character value
letter = chr(64+j)
print(letter, end="")

#print a new line after every row of alphabet series
print()

Output

Enter the height of pattern(1-26): 8
A
AB
ABC
ABCD
ABCDE
ABCDEF
ABCDEFG
ABCDEFGH

Complexity Analysis

• Time Complexity: O(N 2 ), In the program, we are using a nested loop, that makes the time complexity Quadratic.
• Space Complexity: O(1), there is no extra space usage in the program so the space complexity is constant.

Wrapping Up!

Now let's wrap this programming tutorial on " Write a Program to Print the pattern of Alphabets". You may find this problem in your upcoming programming interview, so it's better to learn its logic. All we have done in the program to convert a specific range of ASCII code into characters and print them repeatedly.