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Find the real and imaginary part of a Complex number
• Difficulty Level : Easy
• Last Updated : 05 May, 2020

Given a complex number Z, the task is to determine the real and imaginary part of this complex number.

Examples:

Input: z = 3 + 4i
Output: Real part: 3, Imaginary part: 4

Input: z = 6 – 8i
Output: Real part: 6, Imaginary part: 8

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: A complex number can be represented as Z = x + yi, where x is real part and y is imaginary.
We will follow the below steps to separate out real and imaginary part

1. Find out the index of + or operator in the string
2. Real part will be a substring starting from index 0 to a length (index of operator – 1)
3. Imaginary part will be a substring starting from index (index of operator + 1) to (length of string – index of operator – 2)

Implementation:

## C++

 `// C++ program to find the real and``// imaginary parts of a Complex Number``#include ``using` `namespace` `std;`` ` `// Function to find real and imaginary``// parts of a complex number``void` `findRealAndImag(string s)``{``    ``// string length stored in variable l``    ``int` `l = s.length();`` ` `    ``// variable for the index of the separator``    ``int` `i;`` ` `    ``// Storing the index of '+'``    ``if` `(s.find(``'+'``) < l) {``        ``i = s.find(``'+'``);``    ``}``    ``// else storing the index of '-'``    ``else` `{``        ``i = s.find(``'-'``);``    ``}`` ` `    ``// Finding the real part``    ``// of the complex number``    ``string real = s.substr(0, i);`` ` `    ``// Finding the imaginary part``    ``// of the complex number``    ``string imaginary = s.substr(i + 1, l - i - 2);`` ` `    ``cout << ``"Real part: "` `<< real << ``"\n"``;``    ``cout << ``"Imaginary part: "``         ``<< imaginary << ``"\n"``;``}`` ` `// Driver code``int` `main()``{``    ``string s = ``"3+4i"``;`` ` `    ``findRealAndImag(s);`` ` `    ``return` `0;``}`

## Java

 `// Java program to find the real and``// imaginary parts of a Complex Number ``class` `GFG``{``    ``// Function to find real and imaginary``    ``// parts of a complex number``    ``static` `void` `findRealAndImag(String s)``    ``{``        ``// string length stored in variable l``        ``int` `l = s.length();``      ` `        ``// variable for the index of the separator``        ``int` `i;``      ` `        ``// Storing the index of '+'``        ``if` `(s.indexOf(``'+'``) != -``1``) {``            ``i = s.indexOf(``'+'``);``        ``}`` ` `        ``// else storing the index of '-'``        ``else` `{``            ``i = s.indexOf(``'-'``);``        ``}``       ` `        ``// Finding the real part``        ``// of the complex number``        ``String real = s.substring(``0``, i);``      ` `        ``// Finding the imaginary part``        ``// of the complex number``        ``String imaginary = s.substring(i + ``1``, l - ``1``);``      ` `        ``System.out.println(``"Real part: "` `+ real );``        ``System.out.println(``"Imaginary part: "``+``              ``imaginary);``    ``}``      ` `    ``// Driver code``    ``public` `static` `void` `main(String []args)``    ``{``        ``String s = ``"3+4i"``;``      ` `        ``findRealAndImag(s);``     ` `    ``}``}`` ` `// This code is contributed by chitranayal`

## Python3

 `# Python3 program to find the real and ``# imaginary parts of a Complex Number `` ` `# Function to find real and imaginary ``# parts of a complex number ``def` `findRealAndImag(s) :`` ` `    ``# string length stored in variable l ``    ``l ``=` `len``(s) `` ` `    ``# variable for the index of the separator ``    ``i ``=` `0` ` ` `    ``# Storing the index of '+' ``    ``if` `(s.find(``'+'``) !``=` `-``1``): ``        ``i ``=` `s.find(``'+'``)``    ``# else storing the index of '-' ``    ``else``:``        ``i ``=` `s.find(``'-'``); `` ` `    ``# Finding the real part ``    ``# of the complex number ``    ``real ``=` `s[:i]`` ` `    ``# Finding the imaginary part ``    ``# of the complex number ``    ``imaginary ``=` `s[i ``+` `1``:l  ``-` `1``]`` ` `    ``print``(``"Real part:"``, real)``    ``print``(``"Imaginary part:"``, imaginary)`` ` `# Driver code ``s ``=` `"3+4i"``; `` ` `findRealAndImag(s); `` ` `# This code is contributed by Sanjit_Prasad`

## C#

 `// C# program to find the real and``// imaginary parts of a Complex Number ``using` `System;`` ` `class` `GFG``{``    ``// Function to find real and imaginary``    ``// parts of a complex number``    ``static` `void` `findRealAndImag(String s)``    ``{``        ``// string length stored in variable l``        ``int` `l = s.Length;``       ` `        ``// variable for the index of the separator``        ``int` `i;``       ` `        ``// Storing the index of '+'``        ``if` `(s.IndexOf(``'+'``) != -1) {``            ``i = s.IndexOf(``'+'``);``        ``}`` ` `        ``// else storing the index of '-'``        ``else` `{``            ``i = s.IndexOf(``'-'``);``        ``}``        ` `        ``// Finding the real part``        ``// of the complex number``        ``String real = s.Substring(0, i);``       ` `        ``// Finding the imaginary part``        ``// of the complex number``        ``String imaginary = s.Substring(i + 1, l - i - 2);``       ` `        ``Console.WriteLine(``"Real part: "` `+ real );``        ``Console.WriteLine(``"Imaginary part: "``+``              ``imaginary);``    ``}``       ` `    ``// Driver code``    ``public` `static` `void` `Main(String []args)``    ``{``        ``String s = ``"3+4i"``;``       ` `        ``findRealAndImag(s);``      ` `    ``}``}`` ` `// This code is contributed by 29AjayKumar`
Output:
```Real part: 3
Imaginary part: 4
```

Performance Analysis:

• Time Complexity: In the above approach, as we are doing a constant number of operations regardless of the length of string, the time complexity is O(1)
• Auxiliary Space Complexity: In the above approach, we are not using any extra space apart from a few variables. So Auxiliary space complexity is O(1)

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