C++ Exercises: Get the fraction part from two given integers representing the numerator and denominator in string format

Last update on December 20 2024 12:24:14 (UTC/GMT +8 hours)

Write a C++ program to get the fraction part from two given integers representing the numerator and denominator in string format.

Sample Input: x = 3
n = 2
Sample Output: 1.5

Sample Solution:

C++ Code :

#include <iostream>
#include <unordered_map>
using namespace std;

// Function to convert a fractional number to its decimal representation
string fraction_to_decimal(int numerator_part, int denominator_part) {
    string result;

    // Handling sign of the result
    if ((numerator_part ^ denominator_part) >> 31 && numerator_part != 0) {
        result = "-"; // If the signs are different, result is negative
    }

    // Taking absolute values for calculation
    auto dvd_part = llabs(numerator_part);
    auto dvs_part = llabs(denominator_part);
    result += to_string(dvd_part / dvs_part); // Calculating integer part
    dvd_part %= dvs_part;

    if (dvd_part > 0) {
        result += "."; // If there's a fractional part
    }

    unordered_map<long long, int> lookup; // Map to track remainder and position

    // Loop to calculate the fractional part
    while (dvd_part && !lookup.count(dvd_part)) {
        lookup[dvd_part] = result.length(); // Storing the remainder's position
        dvd_part *= 10;
        result += to_string(dvd_part / dvs_part); // Append next decimal digit
        dvd_part %= dvs_part; // Update the remainder
    }

    // If the remainder is repeated, it's a recurring decimal
    if (lookup.count(dvd_part)) {
        result.insert(lookup[dvd_part], "("); // Insert "(" at the repeating position
        result.push_back(')'); // Add ")" at the end to indicate the recurring part
    }

    return result; // Return the decimal representation
}

int main(void) {
    // Test cases for the fractional to decimal conversion
    int x = 3;
    int n = 2;
    cout << "\nFractional part of " << x << " and " << n << " = " << fraction_to_decimal(x, n) << endl; 

    x = 4;
    n = 7;
    cout << "\nFractional part of " << x << " and " << n << " = " << fraction_to_decimal(x, n) << endl; 

    return 0; // Return 0 to indicate successful completion
}

Sample Output:

Fractional part of 3 and 2 = 1.5

Fractional part of 4 and 7 = 0.(571428)

Flowchart:

C++ Code Editor:

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