Question

How to multiply two numbers using recursion in C++

Answer 1

#include <iostream>

int multiply(int x, int y) {
    if (y > 0) {
        return (x + multiply(x, y - 1));
    }
 
    if (y < 0) {
        return -multiply(x, -y);
    }
 
    return 0;
}
 
int main()
{
    std::cout << multiply(3, 7) << "\n";
    std::cout << multiply(4, 16) << "\n";
    std::cout << multiply(5, 0) << "\n";
    std::cout << multiply(0, 8) << "\n";
    std::cout << multiply(2, -5) << "\n";
    std::cout << multiply(-4, 6) << "\n";
    std::cout << multiply(-5, -7) << "\n";
}
 
 
 
 
/*
run:
 
21
64
0
0
-10
-24
35
 
*/

 

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