C - Part 47

C Program To Add Two Numbers without using Plus Operator

Lets write a C program to perform addition of 2 numbers without using plus symbol or the addition operator(+).

In this video tutorial we are using ~(tilde symbol) bitwise complement operator to perform the operation to get to the anticipated result.

Example: If user enters 2 numbers. a = 8 and b = 7. To add 8 and 7 we use result = a + b. And the result will be 15. But in this C program we are not using plus(+) operation, but still we must get the same result 15(for above input).

Logic To Add Two Numbers without using Plus Operator

If num = 7;
result = ~num; will give 1s complement of 7, that is -8.
result = -(~num); will give 8.
result = -(~num)-1; will give 7.

Now using this logic, we ask the user to enter 2 numbers. If user enters a = 8 and b = 7. We use the below logic to perform addition, without using plus symbol:

a = 8, b = 7;
add = a – ~b – 1;
add = 8 – (-8) – 1;
add = 8 + 8 – 1;
add = 8 + 7;
add = 15;

This would give proper required result.

Source Code: C Program To Add Two Numbers without using Plus Operator

#include < stdio.h >

int main()
{
    int a, b, add;

    printf("Enter 2 numbers for addition\n");
    scanf("%d%d", &a, &b);

    add = a-~b-1; 

    printf("Addition of %d and %d is %d\n", a, b, add);

    return 0;
}

Output 1:
Enter 2 numbers for addition
1
2
Addition of 1 and 2 is 3

Output 2:
Enter 2 numbers for addition
-1
2
Addition of -1 and 2 is 1

Output 3:
Enter 2 numbers for addition
-1
-2
Addition of -1 and -2 is -3

Output 4:
Enter 2 numbers for addition
-5
5
Addition of -5 and 5 is 0

Output 5:
Enter 2 numbers for addition
5
-10
Addition of 5 and -10 is -5

Video Tutorial: C Program To Add Two Numbers without using Plus Operator

[youtube https://www.youtube.com/watch?v=Gw1lXqCKvdI]

YouTube Link: https://www.youtube.com/watch?v=Gw1lXqCKvdI [Watch the Video In Full Screen.]

Note: These kind of tricky C programming questions can be asked in your viva or company interviews or competitive exams or even in your academic exams. So be prepared.

For list of all c programming interviews / viva question and answers visit: C Programming Interview / Viva Q&A List

For full C programming language free video tutorial list visit:C Programming: Beginner To Advance To Expert

C Program To Subtract Two Numbers without using Minus Operator

Lets write a C program to perform subtraction of 2 numbers without using minus symbol or the subtraction operation(-).

In this video tutorial we are using ~(tilde symbol) bitwise complement operator to perform the operation to get to the anticipated result.

Example: If user enters 2 numbers. a = 15 and b = 5. To subtract 10 from 5 we use result = a – b. And the result will be 10. But in this C program we are not using minus(-) operation, but still we must get the same result 10(for above input).

Logic To Subtract Two Numbers without using Minus Operator

If num = 10;
result = ~num; will give 1s complement of 10, that is -11.
result = ~num+1; will give 2s complement of 10, that is -10.

Now using this logic, we ask the user to enter 2 numbers. If user enters a = 10 and b = 5. We use the below logic to perform subtraction, but without using minus symbol:

a = 10, b = 5;
sub = a + ~b + 1;
sub = 10 + (-6) + 1;
sub = 10 – 6 + 1;
sub = 10 – 5;
sub = 5;

This would give proper required result.

Source Code: C Program To Subtract Two Numbers without using Minus Operator

#include < stdio.h >

int main()
{
    int a, b, sub;

    printf("Enter 2 numbers\n");
    scanf("%d%d", &a, &b);

    sub = a+~b+1;

    printf("Subtraction of %d and %d is %d\n", a, b, sub);

    return 0;
}

Output 1:
Enter 2 numbers
4
10
Subtraction of 4 and 10 is -6

Output 2:
Enter 2 numbers
5
10
Subtraction of 5 and 10 is -5

Output 3:
Enter 2 numbers
10
5
Subtraction of 10 and 5 is 5

Output 4:
Enter 2 numbers
5
5
Subtraction of 5 and 5 is 0

Output 5:
Enter 2 numbers
5
-5
Subtraction of 5 and -5 is 10

Video Tutorial: C Program To Subtract Two Numbers without using Minus Operator

[youtube https://www.youtube.com/watch?v=YG1bDNtO5X8]

YouTube Link: https://www.youtube.com/watch?v=YG1bDNtO5X8 [Watch the Video In Full Screen.]

Note: These kind of tricky C programming questions can be asked in your viva or company interviews or competitive exams or even in your academic exams. So be prepared.

For list of all c programming interviews / viva question and answers visit: C Programming Interview / Viva Q&A List

For full C programming language free video tutorial list visit:C Programming: Beginner To Advance To Expert

C Program To Print Floyd’s Triangle In Reverse

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

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

Logic To Print Floyd’s Triangle In Reverse

We ask the user to input the number of rows of Floyd’s Triangle, we store it inside variable num. We assign 1 to variable nn(natural number). Variable num has the number of natural numbers to be printed in particular row. The inner while loop prints the natural numbers upto num.

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.

Source Code: C Program To Print Floyd’s Triangle In Reverse

#include < stdio.h >

int main()
{
    int num, nn = 1, count;

    printf("Enter no of rows of Floyd's Triangle\n");
    scanf("%d", &num);
    
    printf("\n");
    while(num)
    {
        count = 1;
        while(count <= num)
        {
            printf("%d  ", nn);
            nn++;
            count++;
        }
        printf("\n");
        num--;
    }

    return 0;
}

Output 1:
Enter no of rows of 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 of 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 In Reverse

[youtube https://www.youtube.com/watch?v=7CTZGsGm6yE]

YouTube Link: https://www.youtube.com/watch?v=7CTZGsGm6yE [Watch the Video In Full Screen.]

For list of all c programming interviews / viva question and answers visit: C Programming Interview / Viva Q&A List

For full C programming language free video tutorial list visit:C Programming: Beginner To Advance To Expert

C Program To Print Floyd’s Triangle

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.

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

[youtube https://www.youtube.com/watch?v=5olpgYeAUKU]

YouTube Link: https://www.youtube.com/watch?v=5olpgYeAUKU [Watch the Video In Full Screen.]

For list of all c programming interviews / viva question and answers visit: C Programming Interview / Viva Q&A List

For full C programming language free video tutorial list visit:C Programming: Beginner To Advance To Expert

C program To Check whether a Number is Strong Number or Not

Lets write a C program to check whether user entered number is strong number or not, using nested while loop.

Strong Number: Sum of factorial of a number’s individual digits should be equal to the number itself. Such a number is called Strong Number.

For Example: If user entered number is 145. We find factorial of individual digits of 145 and add it.
i.e., !1 + !4 + !5

(1) + (24) + (120) = 145

So the original number and the sum of factorials of individual digits are both 145. So number 145 is considered as a Strong Number.

Important Topics
Calculate Sum of Digits: C Program
C Program To Find Factorial of a Number

Source Code: C program To Check whether a Number is Strong Number or Not

#include < stdio.h >

int main()
{
    int num, temp, rem, count, fact, sum = 0;

    printf("Enter a number\n");
    scanf("%d", &num);

    temp = num;

    while(num)
    {
        rem = num % 10;

        count = 1;
        fact  = 1;
        while(count <= rem)
        {
            fact = fact * count;
            count++;
        }

        printf("Factorial of %d is %d\n", rem, fact);

        sum = sum + fact;

        num = num / 10;
    }

    if(temp == sum)
    {
        printf("%d is a strong number\n", temp);
    }
    else
    {
        printf("%d is not a strong number\n", temp);
    }

    return 0;
}

Output 1
Enter a number
145
Factorial of 5 is 120
Factorial of 4 is 24
Factorial of 1 is 1
145 is a strong number

Output 2
Enter a number
140
Factorial of 0 is 1
Factorial of 4 is 24
Factorial of 1 is 1
140 is not a strong number

Video Tutorial: C Program To Find Strong Number

[youtube https://www.youtube.com/watch?v=u3yCwqjFCPQ]

YouTube Link: https://www.youtube.com/watch?v=u3yCwqjFCPQ [Watch the Video In Full Screen.]

Logic To Check whether a Number is Strong Number or Not

If user entered number is 145. i.e., num = 145. Using outer while loop we keep fetching digits one by one by using below code.

rem = num % 10;
num = num / 10;

For each iteration the outer loop fetches individual digits of the number. The inner while loop calculates the factorial for that fetched individual digit. Next we keep adding the factorial of each individual digit.

Once the control exits outer while loop we check if the user entered number is equal to the value present in variable sum. If true, then the user entered number is a strong number, if not, its not a strong number.

For list of all c programming interviews / viva question and answers visit: C Programming Interview / Viva Q&A List

For full C programming language free video tutorial list visit:C Programming: Beginner To Advance To Expert