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Lets write C program to print Floyd’s Triangle, using nested while loop.

Floyd’s Triangle: is a right angled Triangle formed with natural numbers.

Related Read:
while loop in C programming
Nested While Loop: C Program

Logic To Print Floyd’s Triangle

We ask the user to input the number of rows of Floyd’s Triangle, we store it inside variable num. We assign 1 to variables count and count1. Variable count is used to print the natural numbers for Floyd’s Triangle. Variable count1 is used to keep track of outer while loop. Variable count2 is used to keep track of inner while loop.

For Example, if user enters num = 5, the following Triangle will be printed:

1
2 3
4 5 6
7 8 9 10
11 12 13 14 15

Note that the Triangle printed is a right angled Triangle and has 5 rows of natural numbers.

Important Note:
Also note that first row has 1 number. Second row has 2 numbers. Third row has 3 numbers and so on. So row number and total numbers in that particular row are always equal in any Floyd’s Triangle.

Outer While loop
In our C program, row number and the total numbers to be printed for that row is present inside variable count1.

Inner While loop
Inner while loop prints natural numbers in each row. Variable count2 is assigned to 1 for each iteration of outer while loop, so that the numbers gets printed from the first position in any selected row.

Source Code: C Program To Print Floyd’s Triangle

#include<stdio.h>

int main()
{
    int num, count = 1, count1 = 1, count2;

    printf("Enter no of rows for Floyd's Triangle\n");
    scanf("%d", &num);

    printf("\n");

    while(count1 <= num)
    {
        count2 = 1;
        while(count2 <= count1)
        {
            printf("%d  ", count);
            count++;
            count2++;
        }
        count1++;
        printf("\n");
    }

    return 0;
}

Output 1:
Enter no of rows for Floyd’s Triangle
5

1
2 3
4 5 6
7 8 9 10
11 12 13 14 15

Output 2:
Enter no of rows for Floyd’s Triangle
14

1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44 45
46 47 48 49 50 51 52 53 54 55
56 57 58 59 60 61 62 63 64 65 66
67 68 69 70 71 72 73 74 75 76 77 78
79 80 81 82 83 84 85 86 87 88 89 90 91
92 93 94 95 96 97 98 99 100 101 102 103 104 105

Video Tutorial: C Program To Print Floyd’s Triangle

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