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C++ Exercises: Find the missing element from two given arrays of integers except one element

C++ Array: Exercise-22 with Solution

Write a C++ program to find the missing element from two given arrays of integers except one element.

Sample Solution:

C++ Code :

#include <iostream>
using namespace std;
 
int findMissing(int array1[], int array2[], int s1, int s2)
{
    int result = 0;
    for (int i=0; i<s1; i++)
       result = result^array1[i];
    for (int i=0; i<s2; i++)
       result = result^array2[i];
 
    return result;
}
int main()
{
    int array1[] = {3, 1, 5, 7, 9};
    int array2[] = {3, 7, 5, 9};
     int mn;
     int s1 = sizeof(array1) / sizeof(array1[0]);
    int s2 = sizeof(array2) / sizeof(array2[0]);
        if (s1 != s2-1 && s2 != s1-1)
    {
        cout << "Invalid Input";
        return 0;
    }
    
    cout << "Original arrays: ";
    
    cout << "\nFirst array: ";
    for (int i=0; i < s1; i++) 
    cout << array1[i] <<" ";
    
    cout << "\nSecond array: ";
    for (int i=0; i < s2; i++) 
    cout << array2[i] <<" ";
    
    mn = findMissing(array1, array2, s1, s2);
    cout <<"\nMissing number: " << mn;
    return 0; 
}

Sample Output:

Original arrays: 
First array: 3 1 5 7 9 
Second array: 3 7 5 9 
Missing number: 1

Flowchart:

Flowchart: Find the missing element from two given arrays of intgers except one element

C++ Code Editor:

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C++ Programming: Tips of the Day

Can I assume (bool)true == (int)1 for any C++ compiler?

According to the standard, you should be safe with that assumption. The C++ bool type has two values - true and false with corresponding values 1 and 0.

The thing to watch about for is mixing bool expressions and variables with BOOL expression and variables. The latter is defined as FALSE = 0 and TRUE != FALSE, which quite often in practice means that any value different from 0 is considered TRUE.

A lot of modern compilers will actually issue a warning for any code that implicitly tries to cast from BOOL to bool if the BOOL value is different than 0 or 1

Ref: https://bit.ly/3PWhs5N