C Array Pointers

Calculate Sum of all Elements of an Array using Pointers as Arguments

#include 

#include 

void main()

{

    static int array[5] = { 200, 400, 600, 800, 1000 };

    int sum;

    int addnum(int *ptr);

    sum = addnum(array);

    printf("Sum of all array elements = %5d\n", sum);

}

int addnum(int *ptr)

{

    int index, total = 0;

    for (index = 0; index < 5; index++)

    {

        total += *(ptr + index);

    }

    return(total);

   getch();

}

Output

            Sum of all array elements =  3000

Accept an Array & Swap Elements using Pointers

#include 

#include 

void swap34(float *ptr1, float *ptr2);

void main()

{

    float x[10];

    int i, n;

    clrscr();

    printf("How many Elements...\n");

    scanf("%d", &n);

    printf("Enter Elements one by one\n");

    for (i = 0; i < n; i++)

    {

        scanf("%f", x + i);

    }

    swap34(x + 2, x + 3);

    printf("\nResultant Array...\n");

    for (i = 0; i < n; i++)

    {

        printf("X[%d] = %f\n", i, x[i]);

    }

}

void swap34(float *ptr1, float *ptr2 )

{

    float temp;

    temp = *ptr1;

    *ptr1 = *ptr2;

    *ptr2 = temp;

getch();

}

Output

How many Elements...

4

Enter Elements one by one

23

67

45

15

Resultant Array...

X[0] = 23.000000

X[1] = 67.000000

X[2] = 15.000000

X[3] = 45.000000

Read an Array and Search for an Element

           #include 

#include  

void main()

{

    int array[20];

    int i, low, mid, high, key, size;

    clrscr();

    printf("Enter the size of an array\n");

    scanf("%d", &size);

    printf("Enter the array elements\n");

    for (i = 0; i < size; i++)

    {

        scanf("%d", &array[i]);

    }

    printf("Enter the key\n");

    scanf("%d", &key);

    low = 0;

    high = (size - 1);

    while (low <= high)

    {

        mid = (low + high) / 2;

        if (key == array[mid])

        {

            printf("Successful search\n");

            return;

        }

        if (key < array[mid])

            high = mid - 1;

        else

            low = mid + 1;

    }

    printf("unsuccessful search\n");

    getch();

}

Output

Enter the size of an array

4

Enter the array elements

90

560

300

390

Enter the key

90

Successful search

Enter the size of an array

4

Enter the array elements

100

500

580

470

Enter the key

300

Unsuccessful search

Merge and Sort Elements of 2 different arrays

#include 

#include 

void Merge(int * , int , int , int );

void MergeSort(int *array, int left, int right)

{

    int middle = (left+right)/2;

        if(left<right)

    {

        MergeSort(array, left, middle);

        MergeSort(array, middle + 1, right);

        Merge(array, left, middle, right);

    }

}

void Merge(int *array, int left, int middle, int right)

{

        int tmp[right - left + 1];

    int pos = 0, leftposition = left, rightposition = middle + 1;

    while (leftposition <= middle && rightposition <= right)

    {

        if (array[leftposition] < array[rightposition])

        {

            tmp[pos++] = array[leftposition++];

        }

        else

        {

            tmp[pos++] = array[rightposition++];

        }

    }

    while (leftposition <= middle)

        tmp[pos++] = array[leftposition++];

    while (rightposition <= right)

        tmp[pos++] = array[rightposition++];

    int i;

    for (i = 0; i < pos; i++)

    {

        array[i + left] = tmp[i];

    }

    return;

}

int main()

{

    int size;

    printf("\n enter the size of an array");

    scanf("%d", &size);

    int array[size];

    int i, j, k;

    printf("\n enter the array elements");

    for (i = 0; i < size; i++)

    {

        scanf("%d", &array[i]);

    }

        MergeSort(array, 0, size - 1);

    for (i = 0; i < size; i++)

    {

        printf("%d ", array[i]);

    }

    printf("\n");

    return 0;

    getch();

}

Output

Enter the size of an array10

Enter the array elements-12

10

45

32

49

-58

69

38

98

34

-58 -12 10 32 34 38 45 49 69 98