# 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 sum.

Program:

## C

 `// C program to swap the two numbers ` `// using command line arguments ` ` `  `#include ` `#include /* 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); ` `        ``num2 = ``atoi``(argv); ` ` `  `        ``// 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:

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