NEW PROGRAMMES C C

Reverse a Stack using Recursion
#include
#include
#include

struct node
{
    int a;
    struct node *next;
};

void generate(struct node **);
void display(struct node *);
void stack_reverse(struct node **, struct node **);
void delete(struct node **);

int main()
{
    struct node *head = NULL;

    generate(&head);
    printf("\nThe sequence of contents in stack\n");
    display(head);
    printf("\nInversing the contents of the stack\n");
    if (head != NULL)
    {
        stack_reverse(&head, &(head->next));
    }
    printf("\nThe contents in stack after reversal\n");
    display(head);
    delete(&head);

    return 0;
}

void stack_reverse(struct node **head, struct node **head_next)
{
    struct node *temp;

    if (*head_next != NULL)
    {
         temp = (*head_next)->next;
        (*head_next)->next = (*head);
        *head = *head_next;
        *head_next = temp;
        stack_reverse(head, head_next);
    }
}

void display(struct node *head)
{
    if (head != NULL)
    {
        printf("%d  ", head->a);
        display(head->next);
    }
}

void generate(struct node **head)
{
    int num, i;
    struct node *temp;

    printf("Enter length of list: ");
    scanf("%d", &num);
    for (i = num; i > 0; i--)
    {
        temp = (struct node *)malloc(sizeof(struct node));
        temp->a = i;
        if (*head == NULL)
        {
            *head = temp;
            (*head)->next = NULL;
        }
        else
        {
            temp->next = *head;
            *head = temp;
        }
    }
}

void delete(struct node **head)
{
    struct node *temp;
    while (*head != NULL)
    {
        temp = *head;
        *head = (*head)->next;
        free(temp);
    }
}

Output

Enter length of list: 10

The sequence of contents in stack
1  2  3  4  5  6  7  8  9  10
Inversing the contents of the stack

The contents in stack after reversal
10  9  8  7  6  5  4  3  2  1
Implement Selection Sort Recursively
#include
#include  
void selection(int [], int, int, int, int);

int main()
{
    int list[30], size, temp, i, j;

    printf("Enter the size of the list: ");
    scanf("%d", &size);
    printf("Enter the elements in list:\n");
    for (i = 0; i < size; i++)
    {
        scanf("%d", &list[i]);
    }
    selection(list, 0, 0, size, 1);
    printf("The sorted list in ascending order is\n");
    for (i = 0; i < size; i++)
    {
        printf("%d  ", list[i]);
    }

    return 0;
}

void selection(int list[], int i, int j, int size, int flag)
{
    int temp;

    if (i < size - 1)
    {
        if (flag)
        {
            j = i + 1;
        }
        if (j < size)
        {
            if (list[i] > list[j])
            {
                temp = list[i];
                list[i] = list[j];
                list[j] = temp;
            }
            selection(list, i, j + 1, size, 0);
        }
        selection(list, i + 1, 0, size, 1);
    }
}

Output

Enter the size of the list: 5
Enter the elements in list:
23
45
64
12
34
The sorted list in ascending order is
12  23  34  45  64
Perform Matrix Multiplication using Recursion
#include
#include
void multiply(int, int, int [][10], int, int, int [][10], int [][10]);
void display(int, int, int[][10]);

int main()
{
    int a[10][10], b[10][10], c[10][10] = {0};
    int m1, n1, m2, n2, i, j, k;

    printf("Enter rows and columns for Matrix A respectively: ");
    scanf("%d%d", &m1, &n1);
    printf("Enter rows and columns for Matrix B respectively: ");
    scanf("%d%d", &m2, &n2);
    if (n1 != m2)
    {
        printf("Matrix multiplication not possible.\n");
    }
    else
    {
        printf("Enter elements in Matrix A:\n");
        for (i = 0; i < m1; i++)
        for (j = 0; j < n1; j++)
        {
            scanf("%d", &a[i][j]);
        }
        printf("\nEnter elements in Matrix B:\n");
        for (i = 0; i < m2; i++)
        for (j = 0; j < n2; j++)
        {
            scanf("%d", &b[i][j]);
        }
        multiply(m1, n1, a, m2, n2, b, c);
    }
    printf("On matrix multiplication of A and B the result is:\n");
    display(m1, n2, c);
}

void multiply (int m1, int n1, int a[10][10], int m2, int n2, int b[10][10], int c[10][10])
{
    static int i = 0, j = 0, k = 0;

    if (i >= m1)
    {
        return;
    }
    else if (i < m1)
    {
        if (j < n2)
        {
            if (k < n1)
            {
                c[i][j] += a[i][k] * b[k][j];
                k++;
                multiply(m1, n1, a, m2, n2, b, c);
            }
            k = 0;
            j++;
            multiply(m1, n1, a, m2, n2, b, c);
        }
        j = 0;
        i++;
        multiply(m1, n1, a, m2, n2, b, c);
    }
}

void display(int m1, int n2, int c[10][10])
{
    int i, j;

    for (i = 0; i < m1; i++)
    {
        for (j = 0; j < n2; j++)
        {
            printf("%d  ", c[i][j]);
        }
        printf("\n");
    }
}

Output

Enter rows and columns for Matrix A respectively: 2
2
Enter rows and columns for Matrix B respectively: 2
2
Enter elements in Matrix A:
12 56
45 78

Enter elements in Matrix B:
2 6
5 8
On matrix multiplication of A and B the result is:
304  520
480  894
Input Few Numbers & Perform Merge Sort on them using Recursion
#include
#include
void mergeSort(int [], int, int, int);
void partition(int [],int, int);

int main()
{
    int list[50];
    int i, size;

    printf("Enter total number of elements:");
    scanf("%d", &size);
    printf("Enter the elements:\n");
    for(i = 0; i < size; i++)
    {
         scanf("%d", &list[i]);
    }
    partition(list, 0, size - 1);
    printf("After merge sort:\n");
    for(i = 0;i < size; i++)
    {
         printf("%d   ",list[i]);
    }

   return 0;
}

void partition(int list[],int low,int high)
{
    int mid;

    if(low < high)
    {
        mid = (low + high) / 2;
        partition(list, low, mid);
        partition(list, mid + 1, high);
        mergeSort(list, low, mid, high);
    }
}

void mergeSort(int list[],int low,int mid,int high)
{
    int i, mi, k, lo, temp[50];

    lo = low;
    i = low;
    mi = mid + 1;
    while ((lo <= mid) && (mi <= high))
    {
        if (list[lo] <= list[mi])
        {
            temp[i] = list[lo];
            lo++;
        }
        else
        {
            temp[i] = list[mi];
            mi++;
        }
        i++;
    }
    if (lo > mid)
    {
        for (k = mi; k <= high; k++)
        {
            temp[i] = list[k];
            i++;
        }
    }
    else
    {
        for (k = lo; k <= mid; k++)
        {
             temp[i] = list[k];
             i++;
        }
    }

    for (k = low; k <= high; k++)
    {
        list[k] = temp[k];
    }
}

Output

Enter total number of elements:5
Enter the elements:
12
36
22
76
54
After merge sort:
12   22   36   54   76
Find the Nth Fibonacci Number using Recursion
#include
#include
int fibo(int);

int main()
{
    int num;
    int result;

    printf("Enter the nth number in fibonacci series: ");
    scanf("%d", &num);
    if (num < 0)
    {
        printf("Fibonacci of negative number is not possible.\n");
    }
    else
    {
        result = fibo(num);
        printf("The %d number in fibonacci series is %d\n", num, result);
    }
    return 0;
}
int fibo(int num)
{
    if (num == 0)
    {
        return 0;
    }
    else if (num == 1)
    {
        return 1;
    }
    else
    {
        return(fibo(num - 1) + fibo(num - 2));
    }
}

Output

Enter the nth number in fibonacci series: 8
The 8 number in fibonacci series is 21

$ a.out
Enter the nth number in fibonacci series: 12
The 12 number in fibonacci series is 144
Find the Biggest Number in an Array of Numbers using Recursion
#include
#include  
int large(int[], int, int);

int main()
{
    int size;
    int largest;
    int list[20];
    int i;

    printf("Enter size of the list:");
    scanf("%d", &size);
    printf("Printing the list:\n");
    for (i = 0; i < size ; i++)
    {
        list[i] = rand() % size;
        printf("%d\t", list[i]);
    }
    if (size == 0)
    {
        printf("Empty list\n");
    }
    else
    {
        largest = list[0];
        largest = large(list, size - 1, largest);
        printf("\nThe largest number in the list is: %d\n", largest);
    }
}
int large(int list[], int size, int largest)
{
    if (size == 1)
        return largest;

    if (size > -1)
    {
        if (list[size] > largest)
        {
            largest = list[size];
        }
        return(largest = large(list, size - 1, largest));
    }
    else
    {
        return largest;
    }
}

Output

Enter size of the list:8
Printing the list:
7 6 1 3 1 7 2 4
The largest number in the list is: 7
Recursion to Search an Element in Array
#include
#include
int search(int [], int, int);
int main()
{
    int size, index, key;
    int list[20];
    int count = 0;
    int i;
    clrscr();
    printf("Enter the size of the list: ");
    scanf("%d", &size);
    index = size;
    printf("Printing the list:\n");
    for (i = 0; i < size; i++)
    {
        list[i] = rand() % size;
        printf("%d\t", list[i]);
    }
    printf("\nEnter the key to search: ");
    scanf("%d", &key);
    while (index > 0)
    {
        index = search(list, index - 1, key);
        printf("Key found at position: %d\n", index + 1);
        count++;
    }
    if (!count)
        printf("Key not found.\n");
    return 0;
}
int search(int array[], int size, int key)
{
    int location;
    if (array[size] == key)
    {
        return size;
    }
    else if (size == -1)
    {
        return -1;
    }
    else
    {
        return (location = search(array, size - 1, key));
    }
}

Output

Enter the size of the list: 10

Printing the list:
3 6 7 5 3 5 6 2 9 1

Enter the key to search: 5

Key found at position: 6

Key found at position: 4