Merge two sorted arrays using C++.

Problem statement

Given 2 sorted arrays list. Write a function to merge given two sorted arrays into one

Arr1[] = {10,15, 17, 20} Arr2[] = {5, 9, 13, 19} Result[] = {5, 9, 10, 13, 15, 17, 19, 20}

Algorithm

1. Traverse both array    1.1. If arr1[i] < arr2[j]       1.1.1. Add arr[i] to new array       1.1.2. Increment ‘i’ and index of result array ‘k’    1.2. If arr2[i] < arr1[j]       1.2.1. Add arr[j] to new array       1.2.2. Increment ‘j’ and index of result array ‘k’ 2. Repeat procedure until both arrays are exhausted 3. Return resultant array

Example

#include <iostream> #define SIZE(arr) (sizeof(arr) / sizeof(arr[0])) using namespace std; void mergeSortedArrays(int *arr1, int n1, int *arr2, int n2, int *result){    int i, j, k;    i = 0;    j = 0;    k = 0;    while (i < n1 && j < n2) {       if (arr1[i] < arr2[j]) {          result[k] = arr1[i];          ++k;          ++i;       } else {          result[k] = arr2[j];          ++k;          ++j;       }    }    while (i < n1) {       result[k] = arr1[i];       ++k;       ++i;    }    while (j < n2) {       result[k] = arr2[j];       ++k;       ++j;    } } void dispalyArray(int *arr, int n){    for (int i = 0; i < n; ++i) {       cout << arr[i] << " ";    }    cout << endl; } int main(){    int arr1[] = {10, 15, 17, 20};    int arr2[] = {5, 9, 7, 13, 19};    int result[SIZE(arr1) + SIZE(arr2)];    cout << "First sorted array:" << endl;    dispalyArray(arr1, SIZE(arr1));    cout << "Second sorted array:" << endl;    dispalyArray(arr2, SIZE(arr2));    mergeSortedArrays(arr1, SIZE(arr1), arr2, SIZE(arr2), result);    cout << "Final sorted array:" << endl;    dispalyArray(result, SIZE(result));    return 0; }

Output

When you compile and execute the above program. It generates the following output −

First sorted array: 10 15 17 20 Second sorted array: 5 9 7 13 19 Final sorted array: 5 9 7 10 13 15 17 19 20