C programming - Part 24

C Program To Calculate Sum of First 7 Terms of Natural Logarithm

The Natural Logarithm can be approximated by the following series:

(x – 1 / x) + 1/2 (x – 1 / x)² + 1/2 (x – 1 / x)³ + 1/2 (x – 1 / x)⁴ + ..

If x is input through the keyboard, write a C program to calculate the sum of first seven terms of this series.

Video Tutorial: C Program To Calculate Sum of First 7 Terms of Natural Logarithm

[youtube https://www.youtube.com/watch?v=8mVIyfub9o4]

YouTube Link: https://www.youtube.com/watch?v=8mVIyfub9o4 [Watch the Video In Full Screen.]

Source Code: C Program To Calculate Sum of First 7 Terms of Natural Logarithm

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

int main()
{
    int count;
    float x, result = 0.0;

    printf("Enter value of x\n");
    scanf("%f", &x);

    for(count = 1; count <= 7; count++)
    {
        if(count == 1)
        {
            result = (x - 1) / x;
        }
        else
        {
            result = result + pow( (x - 1) / x, count) * 0.5;
        }
    }

    printf("Result of first 7 terms = %0.2f\n", result);

    return 0;
}

Output 1
Enter value of x
5
Result of first 7 terms = 1.98

Output 2
Enter value of x
14
Result of first 7 terms = 3.10

Logic To Calculate Sum of First 7 Terms of Natural Logarithm

According to the problem statement it is clear that we need sum of first 7 terms of Natural Logarithm. So we initialize the loop counter variable count to 1 and iterate through the for loop until count value is less than or equal to 7.

Inside for loop we calculate the value of first 7 terms in the series and store it inside variable result.

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C Program To Draw Pyramid of Numbers, using For Loop

Lets write a C program to draw / display / print a four row pyramid formed from numbers 1 to 10.

Video Tutorial: C Program To Draw Pyramid of Numbers, using For Loop

[youtube https://www.youtube.com/watch?v=Z-uVxVnXqgE]

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

Source Code: C Program To Draw Pyramid of Numbers, using For Loop

#include<stdio.h>
int main()
{
    int num = 4, row, col, space, count = 1;
    float i = -7;


    for(row = 1; row <= num; row++)
    {
        for(space = i; space <= (num-row); space++)
        {
            printf(" ");
        }
        for(col = 1; col <= row; col++)
        {
            printf(" %d ", count++);
        }
        i += 0.8;

        printf("\n");
    }

    return 0;
}

Output

                    1
                  2  3
                 4  5  6
               7  8  9  10

Logic To Draw Pyramid of Numbers, using For Loop

Here we already know that the Pyramid we need to print has 4 rows and is formed of numbers 1 to 10.

Outer for loop selects the row number and the number of elements to be printed for that particular selected row. For example, 1st row has 1 element. 2nd row has 2 elements. 3rd row has 3 elements and so on. So the row number and the number of elements in that particular row are always the same.

First inner for loop prints the adequate spacing required for the pyramid. Second inner for loop prints the actual numbers.

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C Program To Draw Pyramid of Stars, using For Loop

Lets write a C program to draw / print / display a pyramid / triangle formed from stars, using nested for loop.

Expected Output for the Input

User Input:
Enter no of rows of Pyramid
5

Output:

    
     *
    ***
   *****
  *******
 *********

Pyramid With 20 Rows
pyramid of stars

Video Tutorial: C Program To Draw Pyramid of Stars, using For Loop

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

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

Logic To Draw Pyramid of Stars, using For Loop

If num = 5;

First Iteration of outer for loop
row = 1;

1st inner for loop
condition:
num – row;
= 5 – 1
= 4
Four spaces gets printed.

2st inner for loop
condition:
2 * row – 1;
= 2 * 1 – 1;
= 2 – 1
= 1
One star gets printed.

Second Iteration of outer for loop
row = 2;

1st inner for loop
condition:
num – row;
= 5 – 2
= 3
Three spaces gets printed.

2st inner for loop
condition:
2 * row – 1;
= 2 * 2 – 1;
= 4 – 1
= 3
Three stars gets printed.

Third Iteration of outer for loop
row = 3;

1st inner for loop
condition:
num – row;
= 5 – 3
= 2
Two spaces gets printed.

2st inner for loop
condition:
2 * row – 1;
= 2 * 3 – 1;
= 6 – 1
= 5
Five stars gets printed.

Forth Iteration of outer for loop
row = 4;

1st inner for loop
condition:
num – row;
= 5 – 4
= 1
One space gets printed.

2st inner for loop
condition:
2 * row – 1;
= 2 * 4 – 1;
= 8 – 1
= 7
Seven stars gets printed.

Fifth Iteration of outer for loop
row = 5;

1st inner for loop
condition:
num – row;
= 5 – 5
= 0
Zero space gets printed.

2st inner for loop
condition:
2 * row – 1;
= 2 * 5 – 1;
= 10 – 1
= 9
Nine stars gets printed.

Source Code: C Program To Draw Pyramid of Stars, using For Loop

#include<stdio.h>

int main()
{
    int num, row, col, space;

    printf("Enter no of rows of Pyramid\n");
    scanf("%d", &num);

    for(row = 1; row <= num; row++)
    {
        for(space = 1; space <= (num-row); space++)
        {
            printf(" ");
        }
        for(col = 1; col <= (2*row-1); col++)
        {
            printf("*");
        }
        printf("\n");
    }

    return 0;
}

Output 1:
Enter no of rows of Pyramid
5

     *
    ***
   *****
  *******
 *********

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

C Program To Display Right Angled Triangle With Alphabets, using For Loop

Lets write a C program to display/print/output a right angled triangle pattern formed with Capital Letter English Alphabets, using nested for loop.

Expected Output for the Input

If user enters number of rows as 5. Then our C program prints a Right angled Triangle with 5 rows of Capital Letter English Alphabets in it.

User Input:
num = 5;

Output:

A
B C
D E F
G H I J
K L M N O

Video Tutorial: C Program To Display Right Angled Triangle With Alphabets, using For Loop

[youtube https://www.youtube.com/watch?v=WYDm6zrPhkg]

YouTube Link: https://www.youtube.com/watch?v=WYDm6zrPhkg [Watch the Video In Full Screen.]

Logic To Display Right Angled Triangle With Alphabets, using For Loop

If we take a closer look at the right angled triangle, we can see that the number of rows and the number of elements in that row are same. Example, row number 5 has 5 elements. Row number 6 has 6 elements etc. So we store this number in a variable called row. Since row starts from 1, we initialize the variable row to 1.

Outer For Loop

We ask the user to enter the maximum number of rows for the right angled triangle, and store it in address of variable num. Outer for loop selects the row. Outer for loop executes until row value is less than or equal to the user entered number.

Inner For Loop

Inner For loop prints the Alphabets. Printing starts from 1st position. So we initialize variable col to 1. And inner for loop iterates until col is less than or equal to the value present in variable row.

Inside inner for loop we check if the value of variable count is 91(ASCII Value of Z is 91). If true, we resent the value of count to 65(ASCII Value of A is 65).

Note: Row number is equal to the number of elements present in that row.

Source Code: C Program To Display Right Angled Triangle With Alphabets, using For Loop

#include<stdio.h>

int main()
{
    int num, row, col, count = 65;

    printf("Enter no of rows\n");
    scanf("%d", &num);

    printf("\n");
    for(row = 1; row <= num; row++)
    {
        for(col = 1; col <= row; col++)
        {
            if(count == 91)
                count = 65;

            printf("%c  ", count++);
        }
        printf("\n");
    }

    return 0;
}

Output 1:
Enter no of rows
5

A
B C
D E F
G H I J
K L M N O

Output 2:
Enter no of rows
10

A
B  C
D  E  F
G  H  I  J
K  L  M  N  O
P  Q  R  S  T  U
V  W  X  Y  Z  A  B
C  D  E  F  G  H  I  J
K  L  M  N  O  P  Q  R  S
T  U  V  W  X  Y  Z  A  B  C

ASCII value of A is 65

ASCII value of B is 66

ASCII value of C is 67

ASCII value of D is 68

ASCII value of E is 69

ASCII value of F is 70

ASCII value of G is 71

ASCII value of H is 72

ASCII value of I is 73

ASCII value of J is 74

ASCII value of K is 75

ASCII value of L is 76

ASCII value of M is 77

ASCII value of N is 78

ASCII value of O is 79

ASCII value of P is 80

ASCII value of Q is 81

ASCII value of R is 82

ASCII value of S is 83

ASCII value of T is 84

ASCII value of U is 85

ASCII value of V is 86

ASCII value of W is 87

ASCII value of X is 88

ASCII value of Y is 89

ASCII value of Z is 90

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C Program To Print 1+4+9+16 Series, using For Loop

Lets write C program to print/display number series 1 + 4 + 9 + 16 + 25 + using for loop.

Video Tutorial: C Program To Print 1+4+9+16+25 Series, using for Loop

[youtube https://www.youtube.com/watch?v=rUrSZ1PMnOU]

YouTube Link: https://www.youtube.com/watch?v=rUrSZ1PMnOU [Watch the Video In Full Screen.]

Logic To Print 1+4+9+16 number series using for loop

If we analyze the number series, its just addition of square of natural numbers. i.e., (1 x 1) + (2 x 2) + (3 x 3) + (4 x 4) + (5 x 5) + .. etc

We ask the user to enter a number. If user enters num = 5, then we display the first 5 numbers in the series i.e., 1 + 4 + 9 + 16 + 25 +

If user enters num = 10, then we display the first 10 numbers in the series i.e., 1 + 4 + 9 + 16 + 25 + 36 + 49 + 64 + 81 + 100 +

For Loop Logic

We initialize count to 1, as the number series starts from 1. We iterate for loop until count is less than or equal to user entered limit. For each iteration of the for loop we increment the value of count by 1.

Inside for loop we square the value of count and print the result, for each iteration of for loop.

Source Code: C Program To Print 1+4+9+16 Series, using for Loop

#include<stdio.h>

int main()
{
    int limit, count;

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

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

    return 0;
}

Output 1:
Enter the limit
5
1 + 4 + 9 + 16 + 25 +

Output 2:
Enter the limit
10
1 + 4 + 9 + 16 + 25 + 36 + 49 + 64 + 81 + 100 +

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