C++ Exercises: Number as the multiplication of its prime factors

Last update on December 20 2024 12:30:32 (UTC/GMT +8 hours)

Write a C++ program to count from 1 to a specified number and display each number as the product of its prime factors.

Test Data:
Display each number as the product of its prime factors:
From 1 to 23-
1: 1
2: 2
3: 3
4: 2 x 2
5: 5
6: 2 x 3
7: 7
8: 2 x 2 x 2
9: 3 x 3
10: 2 x 5
11: 11
12: 2 x 2 x 3
13: 13
14: 2 x 7
15: 3 x 5
16: 2 x 2 x 2 x 2
17: 17
18: 2 x 3 x 3
19: 19
20: 2 x 2 x 5
21: 3 x 7
22: 2 x 11
23: 23

Sample Solution:

C++ Code :

// Source: shorturl.at/bhjoP

#include <iostream>
#include <iomanip> // Library for manipulating output formatting
using namespace std;

// Function to calculate and display prime factors of a number
void getPrimeFactors(int li) {
    int f = 2;
    string res;
    if (li == 1)
        res = "1"; // For the number 1, there is only one factor which is 1 itself
    else {
        while (true) {
            if (!(li % f)) { // If 'f' is a factor of 'li'
                res += to_string(f); // Append 'f' to the result string
                li /= f;
                if (li == 1)
                    break; // If 'li' becomes 1, break the loop
                res += " x "; // Add 'x' symbol to separate factors in the string
            } else
                f++; // Move to the next number to check if it's a factor
        }
    }
    cout << res << "\n"; // Display the result string containing prime factors
}

int main(int argc, char* argv[]) {
    int n = 23; // Define the upper limit to calculate prime factors (from 1 to 'n')
    cout << "Display each number as the product of its prime factors:";
    cout << "\nFrom 1 to " << n << "-\n";

    for (int x = 1; x <= n; x++) {
        cout << right << setw(4) << x << ": "; // Output formatting to align numbers
        getPrimeFactors(x); // Call function to calculate and display prime factors
    }
    cout << endl;

    return 0;
}

Sample Output:

Display each number as the product of its prime factors:
From 1 to 23-
   1: 1
   2: 2
   3: 3
   4: 2 x 2
   5: 5
   6: 2 x 3
   7: 7
   8: 2 x 2 x 2
   9: 3 x 3
  10: 2 x 5
  11: 11
  12: 2 x 2 x 3
  13: 13
  14: 2 x 7
  15: 3 x 5
  16: 2 x 2 x 2 x 2
  17: 17
  18: 2 x 3 x 3
  19: 19
  20: 2 x 2 x 5
  21: 3 x 7
  22: 2 x 11
  23: 23

Flowchart:

C++ Code Editor:

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