Reverse Alphabet, Diagonal * in C

What You’ll Learn

Print the reverse alphabet line EDCBA on every row, but replace one character per row with * where i == j. The star slides from right to left: EDCB*, EDC*A, ED*BA, E*CBA, *DCBA. Includes a live preview, worked C examples, edge cases, and complexity. Next: Program 18 (palindromic pyramid).

📝 Problem & Approach

Given a top letter (like E), print an n×n grid of reverse letters with one diagonal star per row.

// Classic sample (top = E)
// EDCB*
// EDC*A
// ED*BA
// E*CBA
// *DCBA

Inputs & Outputs

Minimal workflow

for i from 'A' to top:
    for j from top down to 'A':
        if i == j: print '*'
        else: print j
    print newline

Approach comparison

🔮 Live Preview

Enter a top letter from A to Z and draw the reverse diagonal-star grid in the browser.

Press "Draw pattern".

Examples Gallery

Three complete C programs — fixed top E, user-chosen top letter, and a forward A..E diagonal variant. Click View Output to reveal sample console results.

#include <stdio.h>

int main() {
    int i, j;

    for (i = 'A'; i <= 'E'; ++i) {
        for (j = 'E'; j >= 'A'; --j) {
            if (i == j) {
                printf("*");
            } else {
                printf("%c", j);
            }
        }
        printf("\n");
    }

    return 0;
}

EDCB*
EDC*A
ED*BA
E*CBA
*DCBA

#include <stdio.h>

int main() {
    int i, j;
    char top;

    printf("Enter the top letter (like E): ");
    scanf(" %c", &top);

    for (i = 'A'; i <= top; ++i) {
        for (j = top; j >= 'A'; --j) {
            if (i == j) {
                printf("*");
            } else {
                printf("%c", j);
            }
        }
        printf("\n");
    }

    return 0;
}

Enter the top letter (like E): D
DCB*
DC*A
D*BA
*CBA

#include <stdio.h>

int main() {
    int i, j;

    for (i = 'A'; i <= 'E'; ++i) {
        for (j = 'A'; j <= 'E'; ++j) {
            if (i == j) {
                putchar('*');
            } else {
                putchar(j);
            }
        }
        putchar('\n');
    }

    return 0;
}

*BCDE
A*CDE
AB*DE
ABC*E
ABCD*

🔎 Worked Walkthrough — top E

Trace each outer value of i and see which column becomes the star.

Exactly one star per row; the match walks from right to left as i increases.

🎯 Practice Problems

Try these variations to lock in the pattern.

Notes

⏱️ Time and Space Complexity

With n = top − ‘A’ + 1, every row prints n characters, so total work is O(n²).

💡 Best Practices