sum - Part 3

C Program To Calculate the Sum of Natural Numbers From 1 to N using For Loop

Lets write a C program to calculate sum of all natural numbers from 1 to N, using for loop.

Video Tutorial: C Program to Calculate the Sum of Natural Numbers From 1 to N using For Loop

[youtube https://www.youtube.com/watch?v=1jTAWRUXqeM]

YouTube Link: https://www.youtube.com/watch?v=1jTAWRUXqeM [Watch the Video In Full Screen.]

Source Code: C Program to Calculate the Sum of Natural Numbers From 1 to N using For Loop

 
#include<stdio.h>

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

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

    printf("\nNatural Numbers from 1 to %d are:\n", num);

    for(count = 1; count <= num; count++)
    {
        printf("%d\n", count);
        sum   = sum + count;
    }

    printf("\nSum of natural numbers from 1 to %d is: %d\n", num, sum);

    return 0;
}

Output 1:
Enter a positive number
5

Natural Numbers from 1 to 5 are:
1
2
3
4
5

Sum of natural numbers from 1 to 5 is: 15

Output 2:
Enter a positive number
10

Natural Numbers from 1 to 10 are:
1
2
3
4
5
6
7
8
9
10

Sum of natural numbers from 1 to 10 is: 55

Logic To Calculate the Sum of Natural Numbers From 1 to N

We ask the user to enter a positive number and store it in variable num.

For Loop
Variable count is assigned value 1. For loop executes until count value is less than or equal to the user entered number. For each iteration of for loop, count value increments by 1.

Inside for loop, we display the value of count(which is natural number between 1 and user entered number). We also keep adding the value of count to the previous value of variable sum. Once the control exits for loop, sum will have the sum of all the natural numbers between 1 to user entered number.

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C Program To Check If Sum of Square of Sine and Cosine of an Angle is 1

Write a C program to receive value of an angle in degrees and check whether sum of squares of sine and cosine of this angle is equal to 1.

Formula To Convert Angle From Degree To Radian

radian = degree x ( PI / 180.0)
where PI is 3.14159265359

Note: In C programming Language, we’ve a builtin constant M_PI which has value of PI.

Expected Output for the Input

User Input:
Enter angle in Degree
45

Output:
Sum of square of sin(45.00) and cos(45.00) is 1

Logic To Check If Sum of Square of Sine and Cosine of an Angle is 1

User enters the angle in degree. We convert angle from degree to radian.
radian = degree x ( PI / 180.0)
Next we use pow() method present in math.h library to sqaure the values of sin(angle) and cos(angle). We add the square of sin(angle) and cos(angle) and store it inside the variable sum, and display appropriate message to the user.

Video Tutorial: C Program To Check If Sum of Square of Sine and Cosine of an Angle is 1

[youtube https://www.youtube.com/watch?v=wYbhYLcAv3Y]

YouTube Link: https://www.youtube.com/watch?v=wYbhYLcAv3Y [Watch the Video In Full Screen.]

Source Code: C Program To Check If Sum of Square of Sine and Cosine of an Angle is 1

#include<stdio.h>
#include<math.h>

int main()
{
    float sum = 0, angle, temp;

    printf("Enter angle in Degree\n");
    scanf("%f", &angle);

    temp   = angle;

    angle  = angle * ( M_PI / 180.0 );

    sum    = (  pow(sin(angle), 2) + pow(cos(angle), 2)  );

    if(sum == 1)
    {
        printf("Sum of square of sin(%0.2f) and cos(%0.2f) is 1\n", temp, temp);
    }
    else
    {
        printf("Sum of square of sin(%0.2f) and cos(%0.2f) is not 1\n", temp, temp);
    }

    return 0;
}

Output 1:
Enter angle in Degree
30
Sum of square of sin(30.00) and cos(30.00) is 1

Output 2:
Enter angle in Degree
45
Sum of square of sin(45.00) and cos(45.00) is 1

Output 3:
Enter angle in Degree
60
Sum of square of sin(60.00) and cos(60.00) is 1

Output 4:
Enter angle in Degree
75
Sum of square of sin(75.00) and cos(75.00) is 1

Output 5:
Enter angle in Degree
90
Sum of square of sin(90.00) and cos(90.00) is 1

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 Find Sum of All Odd Numbers Between Two Integers, using While loop

Lets write a C program to find sum of all odd numbers between range or between 2 integers input by the user.

Odd Number: An odd number is an integer that is not exactly divisible by 2.

For Example: 13 % 2 != 0. When we divide 13 by 2, it does not give a reminder of 0. So number 13 is an odd number.

Note: In this C program we ask the user to input start and end value. We assume that the user enters bigger value for variable end and smaller value for variable start. i.e., start < end

If user enters start = 10 and end = 20. C program finds all the odd numbers between 10 and 20, including 10 and 20. So the odd numbers are 11, 13, 15, 17, 19. We add all these odd numbers and output the sum to the console window. i.e., 11 + 13 + 15 + 17 + 19 = 75. We out put the value 75 as result.

Video Tutorial: C Program To Find Sum of All Odd Numbers Between Range, using While loop

[youtube https://www.youtube.com/watch?v=B_jGvvCh7Ho]

YouTube Link: https://www.youtube.com/watch?v=B_jGvvCh7Ho [Watch the Video In Full Screen.]

Logic To Find Sum of All Odd Numbers Between Two Integers, using While loop

Step 1: We ask the user to enter start and end value.

Step 2: We iterate through the while loop until value of start is less than or equal to value of variable end. Inside while loop we keep incrementing the value of variable start by one for each iteration.

Step 3: For every iteration we check if value present in variable start is an odd number. i.e., start % 2 != 0. If this condition is true, then we add the value present in variable start to the previous value of variable sum.

Step 4: Once the control exits while loop, we print the value present in variable sum – which has the sum of all the odd numbers between the range entered by the user.

Source Code: C Program To Find Sum of All Odd Numbers Between Two Integers, using While loop

#include<stdio.h>

int main()
{
    int start, end, sum = 0;

    printf("Enter start and end value\n");
    scanf("%d%d", &start, &end);

    printf("\nSum of odd numbers from %d to %d is ", start, end);
    while(start <= end)
    {
        if(start % 2 != 0)
        {
            sum = sum + start;
        }
        start++;
    }
    printf("%d\n", sum);

    return 0;
}

Output 1:
Enter start and end value
10
20

Sum of odd numbers from 10 to 20 is 75

Output 2:
Enter start and end value
25
50

Sum of odd numbers from 25 to 50 is 481

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 Find Sum of All Even Numbers Between Two Integers, using While loop

Lets write a C program to find sum of all the even numbers between range or between 2 integers input by the user.

Even Number: An even number is an integer that is exactly divisible by 2.

For Example: 10 % 2 == 0. When we divide 10 by 2, it give a reminder of 0. So number 10 is an even number.

Note: In this C program we ask the user to input start and end value. We assume that the user enters bigger value for variable end and smaller value for variable start. i.e., start < end

If user enters start = 10 and end = 20. C program finds all the even numbers between 10 and 20, including 10 and 20. So the even numbers are 10, 12, 14, 16, 18, 20. We add all these even numbers and output the sum to the console window. i.e., 10 + 12 + 14 + 16 + 18 + 20 = 90. We out put the value 90 as result.

Video Tutorial: C Program To Find Sum of All Even Numbers Between Range, using While loop

[youtube https://www.youtube.com/watch?v=QX3DExBMohQ]

YouTube Link: https://www.youtube.com/watch?v=QX3DExBMohQ [Watch the Video In Full Screen.]

Logic To Find Sum of All Even Numbers Between Two Integers, using While loop

Step 1: We ask the user to enter start and end value.

Step 3: For every iteration we check if value present in variable start is a even number. i.e., start % 2 == 0. If this condition is true, then we add the value present in variable start to the previous value of variable sum.

Step 4: Once the control exits while loop, we print the value present in variable sum – which has the sum of all the even numbers between the range entered by the user.

Source Code: C Program To Find Sum of All Even Numbers Between Two Integers, using While loop

#include<stdio.h>
int main()
{
    int start, end, sum = 0;

    printf("Enter start and end value\n");
    scanf("%d%d", &start, &end);

    printf("\nSum of even no's from %d to %d is ", start, end);
    while(start <= end)
    {
        if(start % 2 == 0)
        {
            sum = sum + start;
        }
        start++;
    }
    printf("%d\n", sum);

    return 0;
}

Output 1:
Enter start and end value
10
20

Sum of even no’s from 10 to 20 is 90

Output 2:
Enter start and end value
25
50

Sum of even no’s from 25 to 50 is 494

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 Find Sum of All Even Numbers From 1 To N, using While loop

Lets write a C program to find sum of all the even numbers from 1 to N, using while loop.

Even Number: An even number is an integer that is exactly divisible by 2.

For Example: 8 % 2 == 0. When we divide 8 by 2, it give a reminder of 0. So number 8 is an even number.

If user enters num = 5. Even numbers between 1 to 5 are 2, 4. So we add 2 and 4. i.e., 2 + 4 = 6. We display 6 to the console window as result.

Video Tutorial: C Program To Find Sum of All Even Numbers From 1 To N, using While loop

[youtube https://www.youtube.com/watch?v=EZeusHqc0Rc]

YouTube Link: https://www.youtube.com/watch?v=EZeusHqc0Rc [Watch the Video In Full Screen.]

Logic To Find Sum of All Even Numbers From 1 To N, using While loop

Since we are checking for even numbers from 1 to user entered number, we assign value of variable count to 1. While loop keeps iterating until value of count is less than or equal to value of user input number. For each iteration of while loop we increment the value of count by 1.

Inside while loop we check for the condition, count%2 == 0. If it’s true, then we add the value present inside variable count to previous value present in variable sum.

After the control exits while loop we display the value present in variable sum – which has the sum of all the even numbers from 1 to user entered number.

Source Code: C Program To Find Sum of All Even Numbers From 1 To N, using While loop

#include<stdio.h>

int main()
{
    int num, count = 1, sum = 0;

    printf("Enter the limit\n");
    scanf("%d", &num);

    while(count <= num)
    {
        if(count%2 == 0)
        {
            sum = sum + count;
        }
        count++;
    }
    printf("Sum of Even numbers from 1 to %d is %d\n", num, sum);
    return 0;
}

Output 1:
Enter the limit
5
Sum of Even numbers from 1 to 5 is 6

Output 2:
Enter the limit
20
Sum of Even numbers from 1 to 20 is 110

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