Program 35:Number Pyramid

Program 35:
 

//       1
//      232
//     34543
//    4567654

#include<stdio.h>
main()
{
int i,j,left,right,k,rightcount,count,rows;
printf("Enter number of rows\n");
scanf("%d",&rows);
count=rows-1;
left=1;
right=0;

for(i=1;i<=rows;i++)
{//start of forloop
    for(k=1;k<=count;k++)
    {
        printf(" ");
    }
    for(j=i;j<=left;j++)
    {
        printf("%d",j);
    }
    left+=2;
       if(i!=1)
       {
               for(j=right;j>=i;j--)
             {
            printf("%d",j);
                 }
             
       }
        right+=2;
       printf("\n");
       count--;    
}//end of forloop
}

Explanation:

1. The program starts with initializing
   • rows → Taken from user to print those many rows
   • i,j,k → used as variables.
   • left,right → for printing left and right part of triangle.
   • count → To controll spaces

2. printf("Enter number of rows\n");
   scanf("%d",&rows);

   Taking number of rows as input from user 

3. for(i=1;i<=rows;i++)
   {

   For iterating number of row times 

4. for(k=1;k<=count;k++)
       {
           printf(" ");
       }

   To print spaces left side to achieve shape of pyramid.For example
   __1
   _232
   34543
   beside 1 we have two spaces and beside 2 we have one space and no space beside 3.this is for 3 rows.

5. for(j=i;j<=left;j++)
       {
           printf("%d",j);
       }
       left+=2;

   To print left part of triangle.left+=2 is for incrementing the left by 2 times for each iteration. As if you look at the outputin Iteration 1: 1 is printed and in iteration2: 2,3 are printed  and so on

6. if(i!=1)
          {
                  for(j=right;j>=i;j--)
                {
               printf("%d",j);
                    }
                
          }
           right+=2;

   To print right part of triangle which is skipped if i==1as we dont want to print any thing to the right side of 1 in first row.  right+=2 is for incrementing right by 2 for each iteration.Unlike left right is initialized to 0 as right side printing will start with even number.
   

7.   printf("\n");
           

   To start printing the numbers of pyramid in new line after finishing the iteration
8. count--  is used to decrement the number of spaces to be printed beside the row to achieve the shape of pyramid.If the pyramid is for 4 rows then in 1st row 3 spaces will be printed and in 2nd row 2 spaces will be printed and so on till the end.

 Output: