How to calculate the next multiple of 10 in C++

1 Answer

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#include <iostream>

/*
    next_multiple_of_10:
    --------------------
    Returns the next multiple of 10 greater than or equal to n.

    Algorithm:
    - Add 9 to n: this ensures that any number not already a multiple of 10
      will "spill over" into the next multiple when integer-divided by 10.
    - Divide by 10: integer division truncates toward zero.
    - Multiply by 10: reconstruct the multiple of 10.

    Example:
        n = 23 → (23 + 9) = 32 → 32 / 10 = 3 → 3 * 10 = 30
        n = 40 → (40 + 9) = 49 → 49 / 10 = 4 → 4 * 10 = 40
*/
int next_multiple_of_10(int n) {
    return ((n + 9) / 10) * 10;
}

/*
    main:
    -----
    Demonstrates the function with a sample input.
*/
int main() {
    int nums[] = {23, 10, 0, 1841};
    int length = sizeof(nums) / sizeof(nums[0]);

    for (int i = 0; i < length; i++) {
        std::cout << next_multiple_of_10(nums[i]) << '\n';
    }
}


/*
run:

30
10
0
1850

*/

 



answered Nov 22, 2024 by avibootz
edited 2 days ago by avibootz
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