15.ASCII alphabet value triangle

 I have added numbers to make you understand how we will create this pattern using for loop

• As we know we first see how many lines of code needs to be printed, in this case it is 9
• Since we will take user input it can be simply n which will be taken from user
• As we can see for each line character c is printed
• The character c is incremented after the inner for loop
• So each line there is a different character printed
• For i=1, character printed is 1 a,
• So j loop that will decide what needs to be printed will iterate from 1 to i
• Remember to print "\n" to make it move to next line

Code

#include <stdio.h>

#include <conio.h>

void main() {

    int i, j, n;

    clrscr();

    printf("Enter number of lines: ");

    scanf("%d", &n);

    char currentChar = 'a';

    for (i = 1; i <= n; i++) {

        for (j = 1; j <= i; j++) {

            printf("%c", currentChar);

        }

        currentChar++;  // Move to the next character

        printf("\n");

    }

    getch();

}

Note: scanf is used for taking user input