TCS Coding Practice Question | HCF or GCD of 2 Numbers
Given two numbers, the task is to find the HCF of two numbers using Command Line Arguments. GCD (Greatest Common Divisor) or HCF (Highest Common Factor) of two numbers is the largest number that divides both of them. Examples:
Input: n1 = 10, n2 = 20 Output: 10 Input: n1 = 100, n2 = 101 Output: 1
Approach:
- Since the numbers are entered as Command line Arguments, there is no need for a dedicated input line
- Extract the input numbers from the command line argument
- This extracted numbers will be in String type.
- Convert these numbers into integer type and store it in variables, say num1 and num2
- Find the HCF of the numbers. An efficient solution is to use Euclidean algorithm which is the main algorithm used for this purpose. The idea is, GCD of two numbers doesn’t change if smaller number is subtracted from a bigger number.
- Print or return the HCF
Program:
C
// C program to compute the HCF of two numbers // using command line arguments #include <stdio.h> #include <stdlib.h> /* atoi */ // Function to compute the HCF of two numbers int HCF( int a, int b) { if (b == 0) return a; return HCF(b, a % b); } // Driver code int main( int argc, char * argv[]) { int num1, num2; // Check if the length of args array is 1 if (argc == 1) printf ( "No command line arguments found.\n" ); else { // Get the command line argument and // Convert it from string type to integer type // using function "atoi( argument)" num1 = atoi (argv[1]); num2 = atoi (argv[2]); // Find the HCF and print it printf ( "%d\n" , HCF(num1, num2)); } return 0; } |
Java
// Java program to compute the HCF of two numbers // using command line arguments class GFG { // Function to compute the HCF of two numbers static int HCF( int a, int b) { if (b == 0 ) return a; return HCF(b, a % b); } // Driver code public static void main(String[] args) { // Check if length of args array is // greater than 0 if (args.length > 0 ) { // Get the command line argument and // Convert it from string type to integer type int num1 = Integer.parseInt(args[ 0 ]); int num2 = Integer.parseInt(args[ 1 ]); // Find the HCF int res = HCF(num1, num2); // Print the HCF System.out.println(res); } else System.out.println( "No command line " + "arguments found." ); } } |
Output:
- In C:
- In Java:
Time Complexity: O(log(min(num1,num2)))
Auxiliary Space: O(1)