C++ Exercises: Divide two integers without using multiplication, division and mod operator

Last update on December 20 2024 12:24:13 (UTC/GMT +8 hours)

Write a C++ program to divide two integers (dividend and divisor) without using the multiplication, division and mod operators.

Sample Solution:

C++ Code :

#include <iostream>
using namespace std;

// Function to perform integer division without using the division operator
int divide_result(int dividend_num, int divisor_num) {
    // Handling special case where dividend is INT_MIN and divisor is -1 to prevent integer overflow
    if (dividend_num == INT_MIN && divisor_num == -1) {
        return INT_MAX;
    }

    // Checking if the result will be negative or positive
    bool minus = ((dividend_num > 0) ^ (divisor_num > 0));

    // Using long long to handle absolute values of numbers without causing overflow
    long long num = labs(dividend_num); // Absolute value of dividend
    long long div = labs(divisor_num); // Absolute value of divisor
    int ans = 0; // Result of division

    // Iteratively subtract divisor from dividend to find the quotient
    while (num >= div) {
        long long temp = div;
        long long mul = 1;

        // Doubling the divisor (left shift) to find the nearest multiple of divisor less than or equal to dividend
        while (num >= (temp << 1)) {
            mul <<= 1;
            temp <<= 1;
        }

        ans += mul; // Increment the quotient by the multiple found
        num -= temp; // Subtract the multiple from the dividend
    }

    return minus ? -ans : ans; // Return the final result with sign
}

int main(void) {
    // Test cases for integer division and displaying results
    int dividend_num = 7;
    int divisor_num = 2;
    cout << "\nDividend " << dividend_num << " Divisor " << divisor_num << endl;
    cout << "Result: " << divide_result(dividend_num, divisor_num) << endl;

    dividend_num = -17;
    divisor_num = 5;
    cout << "\nDividend " << dividend_num << " Divisor " << divisor_num << endl;
    cout << "Result: " << divide_result(dividend_num, divisor_num) << endl;

    dividend_num = 35;
    divisor_num = 7;
    cout << "\nDividend " << dividend_num << " Divisor " << divisor_num << endl;
    cout << "Result: " << divide_result(dividend_num, divisor_num) << endl;

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

Sample Output:

Dividend 7 Divisor 2
Result: 3
Dividend -17 Divisor 5
Result: -3
Dividend 35 Divisor 7
Result: 5

Flowchart:

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