How to check the specified rune in Golang String?

In Go language, strings are different from other languages like Java, C++, Python, etc. It is a sequence of variable-width characters where each and every character is represented by one or more bytes using UTF-8 Encoding.
In the Go strings, you are allowed to check the given string contain the specified rune in it using ContainsRune() function. This function returns true if the given string contains the specified rune in it, or this function returns false if the given string does not contain the specified rune. It is defined under the string package so, you have to import string package in your program for accessing ContainsRune function.

Syntax:

func ContainsRune(str string, r rune) bool

Here, str is the string and r is s rune. The return type of this function is bool. Let us discuss this concept with the help of the given examples:

Example 1:

// Go program to illustrate how to check
// the given string containing the rune
package main

import (
    "fmt"
    "strings"
)

func main() {

    // Creating and initializing a string
    // Using shorthand declaration
    string_1 := "Welcome to GeeksforGeeks"
    string_2 := "AppleAppleAppleAppleAppleApple"
    string_3 := "%G%E%E%K%S"

    // Creating and initializing rune
    var r1, r2, r3 rune
    r1 = 'R'
    r2 = 'p'
    r3 = 42

    // Check the given string
    // containing the rune
    // Using ContainsRune function
    res1 := strings.ContainsRune(string_1, r1)
    res2 := strings.ContainsRune(string_2, r2)
    res3 := strings.ContainsRune(string_3, r3)

    // Display the results
    fmt.Printf("String 1: %s , Rune 1: %q , Present or Not: %t",
                                             string_1, r1, res1)

    fmt.Printf("\nString 2: %s , Rune 2: %q , Present or Not: %t",
                                               string_2, r2, res2)

    fmt.Printf("\nString 3: %s , Rune 3: %q , Present or Not: %t",
                                               string_3, r3, res3)

}

Output:

String 1: Welcome to GeeksforGeeks , Rune 1: 'R' , Present or Not: false
String 2: AppleAppleAppleAppleAppleApple , Rune 2: 'p' , Present or Not: true
String 3: %G%E%E%K%S , Rune 3: '*' , Present or Not: false

Example 2:

// Go program to illustrate how to check
// the given string containing the rune
package main

import (
    "fmt"
    "strings"
)

func main() {

    // Creating and Checking the given
    // rune present in the given string
    // Using ContainsRune function
    res1 := strings.ContainsRune("****Welcome, to,"+
                           " GeeksforGeeks****", 60)

    res2 := strings.ContainsRune("Learning x how x to "+
                     "x trim x a x slice of bytes", 'r')

    res3 := strings.ContainsRune("Geeks,for,Geeks, Geek", 'G')

    // Display the results
    fmt.Println("Final Result:")
    fmt.Println("Result 1: ", res1)
    fmt.Println("Result 2: ", res2)
    fmt.Println("Result 3: ", res3)

}

Output:

Final Result:
Result 1:  false
Result 2:  true
Result 3:  true