C program to print half diamond star pattern

Write a C program to print the half diamond star pattern using for loop. How to print half diamond star pattern structure using for loop in C program. Logic to print half diamond star pattern series in C programming.

Input rows: 5

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Required knowledge

Basic C programming, If else, For loop, Nested loop

Read more – Program to print mirrored half diamond star pattern

Logic to print half diamond star pattern

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The above pattern consist of N * 2 – 1rows. For each row columns are in increasing order till N^th row. After N^th row columns are printed in descending order.

Step by step descriptive logic to print half diamond star pattern.

1. Input number of columns to print from user. Store it in a variable say N.
2. Declare a variable as loop counter for each column, say columns = 1.
3. To iterate through rows, run an outer loop from 1 to N * 2 - 1. The loop structure should look like for(i=1; i<N*2; i++).
4. To iterate through columns, run an inner loop from 1 to columns. The loop structure should look like for(j=1; j<=columns; j++). Inside this loop print star.
5. After printing all columns of a row, move to next line.
6. After inner loop check if(i <= N) then increment columns otherwise decrement by 1.

Program to print half diamond star pattern

/**
 * C program to print half diamond star pattern series.
 */

#include<stdio.h>

int main()
{
    int i, j, N, columns;

    /* Input number of columns from user */
    printf("Enter number of columns:");
    scanf("%d",&N);

    columns=1;

    for(i=1;i<N*2;i++)
    {
        for(j=1; j<=columns; j++)
        {
            printf("*");
        }

        if(i < N)
        {
            /* Increment number of columns per row for upper part */
            columns++;
        }
        else
        {
            /* Decrement number of columns per row for lower part */
            columns--;
        }

        /* Move to next line */
        printf("\n");
    }

    return 0;
}

Enter number of columns: 5
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