C++ Exercises: Compute the sum of the numbers in a given array except those numbers starting with 5 followed by atleast one 6

Last update on December 20 2024 12:21:17 (UTC/GMT +8 hours)

Sum Array Excluding Numbers Starting with '5' and Followed by '6'

Write a C++ program to compute the sum of the numbers in a given array except the ones starting with 5 followed by at least one 6. Return 0 if the given array has no integers.

Sample Solution:

C++ Code :

#include <iostream>  // Including input-output stream header file

using namespace std;  // Using standard namespace

// Function definition that calculates the sum of numbers in the array
// excluding those numbers starting with 5 followed by at least one 6
static int test(int nums[], int arr_length)
{
    int sum = 0;  // Initializing variable to store the sum
    int inSection = 0;  // Variable to determine if within the specified section
    int flag = 0;  // Flag to identify the start of the specified section

    // Loop through the array to calculate the sum following the specified conditions
    for (int i = 0; i < arr_length; i++)
    {
        inSection = 0;  // Resetting inSection flag for each iteration

        // Checking if the current number is 5 to potentially begin the specified section
        if (nums[i] == 5)
        {
            inSection = 0;  // Resetting inSection flag
            flag = 1;  // Setting flag to mark the start of the specified section
        }

        // Checking for conditions to identify the section and adjusting the sum accordingly
        if (inSection == 0 && nums[i] == 6)
        {
            if (flag == 1)  // If the start of the section was flagged by 5
            {
                sum = sum - 5;  // Subtracting the previous 5 before 6
                inSection = 1;  // Marking within the specified section
            }
            flag = 0;  // Resetting flag after processing the section
        }

        // If not within the specified section, adding the number to the sum
        if (inSection == 0)
        {
            sum += nums[i];
        }
    }
    return sum;  // Returning the calculated sum
}

int main()
{
    int nums1[] = { 1, 5, 9, 10, 17 };  // Initializing array nums1 with various integers
    int arr_length = sizeof(nums1) / sizeof(nums1[0]);  // Calculating length of array nums1

    // Displaying a message about the sum excluding specified numbers
    cout << "Sum of the numbers of the said array except those numbers starting with 5 followed by at least one 6: " << endl;
    // Calling test function with nums1 and displaying the resulting sum
    cout << test(nums1, arr_length) << endl;

    int nums2[] = { 1, 5, 6, 9, 10, 17 };  // Initializing array nums2 with various integers
    arr_length = sizeof(nums2) / sizeof(nums2[0]);  // Calculating length of array nums2

    // Displaying a message about the sum excluding specified numbers
    cout << "Sum of the numbers of the said array except those numbers starting with 5 followed by at least one 6: " << endl;
    // Calling test function with nums2 and displaying the resulting sum
    cout << test(nums2, arr_length) << endl;

    return 0;  // Returning 0 to indicate successful completion of the program
}

Sample Output:

Sum of the numbers of the said array except those numbers starting with 5 followed by atleast one 6: 
42
Sum of the numbers of the said array except those numbers starting with 5 followed by atleast one 6: 
37

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