TCS Coding Practice Question | Swap two Numbers

Given two numbers, the task is to swap the two numbers using Command Line Arguments. Examples:

Input: n1 = 10, n2 = 20
Output: 20 10

Input: n1 = 100, n2 = 101
Output: 101 100

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
• Get the sum in one of the two given numbers.
• The numbers can then be swapped using the sum and subtraction from the sum.

Program:

C

// C program to swap the two numbers
// using command line arguments

#include <stdio.h>
#include <stdlib.h> /* atoi */

// Function to swap the two numbers
void swap(int x, int y)
{
    // Code to swap ‘x’ and ‘y’

    // x now becomes x+y
    x = x + y;

    // y becomes x
    y = x - y;

    // x becomes y
    x = x - y;

    printf("%d %d\n", x, y);
}

// 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]);

        // Swap the numbers and print it
        swap(num1, num2);
    }
    return 0;
}

Java

// Java program to swap the two numbers
// using command line arguments

class GFG {

    // Function to swap the two numbers
    static void swap(int x, int y)
    {
        // Code to swap ‘x’ and ‘y’

        // x now becomes x+y
        x = x + y;

        // y becomes x
        y = x - y;

        // x becomes y
        x = x - y;

        System.out.println(x + " " + y);
    }

    // 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]);

            // Swap the numbers
            swap(num1, num2);
        }
        else
            System.out.println("No command line "
                               + "arguments found.");
    }
}

Output:

• In C:
• In Java:

Time Complexity: O(1)
Auxiliary Space: O(1)