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

14.Hollow Number Triangle

 

Steps

• Let's count the number of lines i.e 9 so we take it as n
• So i will iterate from 1 to n
• The pattern printed never exceeds i
• For i=1 it is 1, i=9 pattern is there till 9
• So j loop will iterate from 1 to i
• Now coming to the pattern
• We will see where numbers are being printed 
• First vertical line i.e for j=1 each time
• Next horizontal line i.e i=n (i=9 in our example)
• Finally there is a diagonal values 1==1,2==2 so it is i=j
• We will use these conditions in a if condition using logical or
• A difference we see in this pattern is that stars are not being printed
• If we observe the numbers carefully we can understand those are just j values
• So true part will print j values
• False part will print space

Code

#include<stdio.h>

#include<conio.h>

void main(){

int i,j,n;

clrscr();

printf("Enter number of lines ");

scanf("%d",&n);

for(i=1;i<=n;i++)

    {

          for(j=1;j<=i;j++)

               {

                              if(i==n || j==1 || i==j)

                                     {

                                       printf("%d",j);

                                       }

                                else

                                       {

                                         printf(" ");

                                         }   

                   }

           printf("\n");

     }

getch();

}

Note: scanf is used for taking user input

13.Hollow Triangle

 

Steps

• Let's count the number of lines i.e 9 so we take it as n
• So i will iterate from 1 to n
• The pattern printed never exceeds i
• For i=1 it is 1, i=9 pattern is there till 9
• So j loop will iterate from 1 to i
• Now coming to the pattern
• We will see where stars are being printed 
• First vertical line i.e for j=1 each time
• Next horizontal line i.e i=n (i=9 in our example)
• Finally there is a diagonal values 1==1,2==2 so it is i=j
• We will use these conditions in a if condition using logical or
• True part will print *
• False part will print space

Code

#include<stdio.h>

#include<conio.h>

void main(){

int i,j,n;

clrscr();

printf("Enter number of lines ");

scanf("%d",&n);

for(i=1;i<=n;i++)

    {

          for(j=1;j<=i;j++)

               {

                              if(i==n || j==1 || i==j)

                                     {

                                       printf("*");

                                       }

                                else

                                       {

                                         printf(" ");

                                         }   

                   }

           printf("\n");

     }

getch();

}

Note: scanf is used for taking user input

12.Hollow rectangle

 

Steps

• First we will count the number of lines i.e 9
• So i will iterate from 1 to n // n is the value given by user for number of lines
• Now for inner loop j we need to see how many times the pattern is printed i.e 15
• Let it be m
• So j will iterate from 1 to m 
• Now we need to see where stars are printed and where space is printed
• First we can see for the first line (horizontal) and last line (horizontal)
• These two conditions will be i==1 for first line and i==n for last line
• Next we see that each time first star is printed and last star is printed (vertical)
• These two conditions will be j==1 for first vertical line and j==m for last line
• These four conditions can be used together using logical or 
• It will be used in a if  condition inside j loop
• True part will print * 
• False part will print space
• Remember to add "\n"

Code

#include<stdio.h>

#include<conio.h>

void main(){

int i,j,n,m;

clrscr();

printf("Enter number of rows ");

scanf("%d",&n);

printf("Enter number of columns");

scanf("%d",&m);

for(i=1;i<=n;i++)

    {

          for(j=1;j<=m;j++)

               {

                    if(i==1 || i ==n || j==1 || j==m)

                          {

                               printf("*");

                            }

                    else 

                           {

                            printf(" ");    

                             }   

                   }

           printf("\n");

     }

getch();

}

Note: scanf is used for taking user input