How to use the strconv.FormatComplex() function in Golang

Overview

In Golang, the FormatComplex() function of the strconv package is used to convert a given complex number, c, to a string of the form (a+bi), where a is the real part and b is the imaginary component of the complex number. The formatting is done using the format fmt and precision prec.

Syntax

Let’s view the syntax of this function.

func FormatComplex(
    c complex128, 
    fmt byte, 
    prec, bitSize int) string

Parameters

  • c: The complex number to be converted in the string form.
  • fmt: A byte value to define the format:
'b' (-ddddp±ddd, a binary exponent),
'e' (-d.dddde±dd, a decimal exponent),
'E' (-d.ddddE±dd, a decimal exponent),
'f' (-ddd.dddd, no exponent),
'g' ('e' for large exponents, 'f' otherwise),
'G' ('E' for large exponents, 'f' otherwise),
'x' (-0xd.ddddp±ddd, a hexadecimal fraction and binary exponent), or
'X' (-0Xd.ddddP±ddd, a hexadecimal fraction and binary exponent).

  • prec: The precision value that specifies the number of digits printed by the 'e', 'E', 'f', 'g', 'G', 'x', and 'X' formats.

  • bitSize: An integer value that specifies the bitSize bits—64 for the complex64 and 128 for the complex128.

Return value

This function returns the given complex number in the string format (a+bi).

Example

// Using strconv.FormatComplex() Function
package main
import (
	"fmt"
	"strconv"
)
func main() {
    // declaring variable
	var num complex128
	
    // complex value in the form (a+bi)
    //to be converted
	num = complex(5, 3)
    // returns a string type
	fmt.Println(strconv.FormatComplex(num, 'f', 0, 64))
	fmt.Println()
	// reassign value
	num = complex(2.3, 7.91)
    // returns a string type
	fmt.Println(strconv.FormatComplex(num, 'G', 2, 64))
	fmt.Println()
	// reassign value
	num = complex(2, 3)
    // returns a string type
	fmt.Println(strconv.FormatComplex(num, 'E', -1, 128))
	fmt.Println()
	
}

Explanation

  • Line 4: We add the main package.
  • Line 6–9: We import the necessary packages.
  • Line 11–31: We define the main() function, variable num of Complex128 type and assign a value to it using the function complex(). Next, we pass the variable to the FormatComplex() function, which converts the num value to a string.

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