⚡ TL;DR
Print the alphabet pyramid pattern in Dart. Complete working code, expected output, algorithm explanation, and practice variations for beginners learning loops.
The Alphabet Pyramid pattern is a classic loop exercise. Here’s the complete implementation in Dart with working code and output.
Pattern to Print
A
ABA
ABCBA
ABCDCBA
ABCDEDCBAImplementation
void main() {
int n = 5;
for (int i = 1; i <= n; i++) {
String letters = '';
for (int j = 1; j <= i; j++) {
letters += String.fromCharCode(64 + j);
}
String rev = letters.split('').reversed.skip(1).join();
print(' ' * (n - i) + letters + rev);
}
}Output
A
ABA
ABCBA
ABCDCBA
ABCDEDCBAHow It Works
Each row prints ascending letters A..X followed by descending X-1..A, centered with spaces. Uses ASCII arithmetic (A = 65).
Practice Variations
- Try printing the pattern with a different character (e.g.,
#or+) - Modify the code to accept the pattern size as user input
- Combine this pattern with its inverse to create a more complex shape
Complexity
- Time: O(n²) — the grid or line count grows quadratically
- Space: O(1) — only loop counters are needed
Related Patterns
- Alphabet Pyramid in Python
- Alphabet Pyramid in Go
- Alphabet Pyramid in Swift
- Letter Diamond in Dart
- Alphabet Hollow Diamond in Dart
- Repeated Letter Rows in Dart
FAQ
How do you print the Alphabet Pyramid pattern in Dart?
Use nested loops: the outer loop walks through the rows while the inner loop prints the characters or values for each row. The complete Dart implementation with expected output is shown in the sections above.
What is the time complexity of the Alphabet Pyramid pattern in Dart?
The time complexity is O(n²) and the space complexity is O(1), since the pattern is built with a fixed number of loop counters and printed row by row.
Happy coding!
