for loop - Part 8

Nested For Loop In C Programming Language

In this video tutorial we’ll demonstrate the use of nested for loop in C programming language.

Note: For every single iteration of the outer while loop, the inner while loop completes its iterations.

A loop inside another loop is called a nested loop. Consider a nested loop where the outer loop runs x times and consists of another loop inside it. The inner loop runs y times. Then, the total number of times the inner loop runs during the program execution is x*y times.

Total Number of Iterations In Nested Loops
Number of iterations will be equal to the number of iterations in the outer loop multiplied by the number of iterations in the inner loop.

Video Tutorial: Nested For Loop In C Programming Language

[youtube https://www.youtube.com/watch?v=mAV6PW-snmI]

YouTube Link: https://www.youtube.com/watch?v=mAV6PW-snmI [Watch the Video In Full Screen.]

Source Code: Nested For Loop In C Programming Language

#include<stdio.h>

int main()
{
    int i, j;

    for(i = 1; i <= 3; i++)
    {
        printf("\n%d Apple\n", i);

        for(j = 1; j <= 2; j++)
        {
            printf("\t%d Oracle\n", j);
        }
    }

    return 0;
}

Output:

1 Apple
        1 Oracle
        2 Oracle

2 Apple
        1 Oracle
        2 Oracle

3 Apple
        1 Oracle
        2 Oracle

Explanation of above C source code
Here when i value is 1 – in first iteration. j value gets initialized to 1. And inner for loop executes until j value is equal to 2. For second iteration of outer for loop i value is 2, now again j value gets initialized to 1. Now the inner for loop executes until j value is equal to 2. For third iteration of outer for loop i value is 3, now again j value gets initialized to 1. Now again the inner for loop executes until j value is equal to 2.

Source Code: Nested For Loop In C Programming Language

#include<stdio.h>

int main()
{
    int i, j;

    for(i = 1; i <= 3; i++)
    {
        printf("\n%d Apple\n", i);

        for(j = 1; j <= i; j++)
        {
            printf("\t%d Oracle\n", j);
        }
    }

    return 0;
}

Output:

1 Apple
        1 Oracle

2 Apple
        1 Oracle
        2 Oracle

3 Apple
        1 Oracle
        2 Oracle
        3 Oracle

Explanation of above C source code
During first iteration of outer for loop, i value will be 1. Now j gets initialized to 1 and inner for loop iterates until j is equal to the value of i(that is 1). Now for second iteration of outer for loop i value is 2. Again j gets initialized to 1 and inner for loop executes until j value is equal to i. and so on ..

Source Code: Nested For Loop In C Programming Language

#include<stdio.h>

int main()
{
    int i, j, k;

    for(i = 1; i <= 5; i++)
    {
        printf("\n%d Apple\n", i);

        for(j = 1; j <= 3; j++)
        {
            printf("\t%d Oracle\n", j);

            for(k = 1; k <= 2; k++)
            {
                printf("\t\t%d IBM\n", k);
            }
        }
    }

    return 0;
}

Output:

1 Apple
        1 Oracle
                1 IBM
                2 IBM
        2 Oracle
                1 IBM
                2 IBM
        3 Oracle
                1 IBM
                2 IBM

2 Apple
        1 Oracle
                1 IBM
                2 IBM
        2 Oracle
                1 IBM
                2 IBM
        3 Oracle
                1 IBM
                2 IBM

3 Apple
        1 Oracle
                1 IBM
                2 IBM
        2 Oracle
                1 IBM
                2 IBM
        3 Oracle
                1 IBM
                2 IBM

4 Apple
        1 Oracle
                1 IBM
                2 IBM
        2 Oracle
                1 IBM
                2 IBM
        3 Oracle
                1 IBM
                2 IBM

5 Apple
        1 Oracle
                1 IBM
                2 IBM
        2 Oracle
                1 IBM
                2 IBM
        3 Oracle
                1 IBM
                2 IBM

Note: We can have while loop inside a for loop or a for loop inside a while loop. This is also called as nested looping.

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 Calculate Sum of Natural Numbers Between Range using For Loop

Lets write a C program to calculate sum of all natural numbers between the user entered range of numbers, using for loop.

We check if the user has entered smaller number first and then the larger number. If not, we swap the numbers present in the variables min and max.

Video Tutorial: C Program To Calculate Sum of Natural Numbers Between Range using For Loop

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

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

Source Code: C Program To Calculate Sum of Natural Numbers Between Range using For Loop

 
#include<stdio.h>

int main()
{
    int min, max, temp, count, sum = 0;

    printf("Enter 2 positive numbers\n");
    scanf("%d%d", &min, &max);

    if(min > max)
    {
        temp = min;
        min  = max;
        max  = temp;
    }

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

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

    printf("Sum of Natural Numbers from %d to %d is %d\n", min, max, sum);

    return 0;
}

Output 1:
Enter 2 positive numbers
5
10

Natural Numbers from 5 to 10 are:
5
6
7
8
9
10
Sum of Natural Numbers from 5 to 10 is 45

Output 2:
Enter 2 positive numbers
14
10

Natural Numbers from 10 to 14 are:
10
11
12
13
14
Sum of Natural Numbers from 10 to 14 is 60

Logic To Calculate Sum of Natural Numbers Between Range using For Loop

We ask the user to enter minimum and maximum number(i.e., the range) and we store it inside variable min and max. If value of min is greater than value of max, then we swap the values of min and max.

We initialize the variable count to min and iterate through the for loop until count value is less than or equal to value of max. We keep incrementing the value of count by 1 for each iteration of for loop.

Inside for loop we add the value of count to previous value of sum and once the control exits the for loop we display the value present in variable sum.

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 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.

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 Natural Numbers Between Two Numbers using for loop

Lets write a C program to print natural numbers between two user entered numbers, using for loop.

We check if the user has entered smaller number first and then the larger number. If not, we swap the numbers present in the variables min and max.

C Program To Find Factorial of a Number using for Loop

[youtube https://www.youtube.com/watch?v=mF0o3LC1its]

YouTube Link: https://www.youtube.com/watch?v=mF0o3LC1its [Watch the Video In Full Screen.]

Source Code: C Program to Print Natural Numbers Between Two Numbers using for loop

 
#include<stdio.h>

int main()
{
    int min, max, temp, count;

    printf("Enter 2 positive numbers\n");
    scanf("%d%d", &min, &max);

    if(min > max)
    {
        temp = min;
        min  = max;
        max  = temp;
    }

    printf("Natural numbers from %d to %d are:\n", min, max);

    for(count = min; count <= max; count++)
    {
        printf("%d\n", count);
    }

    return 0;
}

Output 1:
Enter 2 positive numbers
10
15
Natural numbers from 10 to 15 are:
10
11
12
13
14
15

Output 2:
Enter 2 positive numbers
15
10
Natural numbers from 10 to 15 are:
10
11
12
13
14
15

Logic To Print Natural Numbers Between Two Numbers using for loop

We ask the user to enter 2 numbers, and store it inside variables min and max. For loop keeps iterating till min is less than or equal to max. We assign the value of min to count and keep incrementing the value of count by 1 for each iteration of the for loop. Once value of count is greater than value of max, control exits for loop.

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 Natural Numbers from 1 to N In Reverse Order using for loop

Lets write a simple C program to print natural numbers from 1 to N in reverse order, using for loop.

C Program to Print Natural Numbers from 1 to N In Reverse Order using for loop

[youtube https://www.youtube.com/watch?v=07rwVW3TVUo]

YouTube Link: https://www.youtube.com/watch?v=07rwVW3TVUo [Watch the Video In Full Screen.]

Source Code: C Program to Print Natural Numbers from 1 to N In Reverse Order using for loop

 
#include<stdio.h>

int main()
{
    int num, count;

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

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

    for(count = num; count >= 1; count--)
    {
        printf("%d\n", count);
    }

    return 0;
}

Output:
Enter a positive number
14

Natural numbers from 14 to 1 are:
14
13
12
11
10
9
8
7
6
5
4
3
2
1

Natural numbers from 10 to 1 are:

Logic To Print Natural Numbers from 1 to N In Reverse Order using for loop

We ask the user to enter a positive number, and store it inside a variable num. We assign value of num to variable count. We iterate through the loop until the count is equal to zero. For example, if user enters num = 5, we iterate the loop 5 times. In for loops modification section we keep decrementing the value of variable count. Once the value of count becomes 0, we exit the for loop. For each iteration we print the value of count.

This way we printout the natural numbers from 1 to N, in reverse order.

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