java string contains char

1String s1 = "My name is GFG"; 
2  
3// prints true 
4System.out.println(s1.contains("GFG")); 
5  
6// prints false 
7System.out.println(s1.contains("geeks")); 
8    

1if (string.contains(character)

1string.indexOf('a')

1 javaCopyimport java.util.*;
2import java.lang.*;
3import java.io.*;
4
5public class Example1 {
6    public static void main(String[] args) {
7        String str = "Character";
8        System.out.println(str.contains("h"));
9        System.out.println(str.contains("Char"));
10        System.out.println(str.contains("ac"));
11        System.out.println(str.contains("v"));
12        System.out.println(str.contains("vl")); 
13    }
14}  
15

1 /*
2    This method returns true if the given string contains
3    the char n. It is necessary due to the
4    obsolescence of some compilers, which requires us
5    to write our own contains method.
6    */
7    public static boolean contains_char (String main, char secondary)
8    {
9        boolean contains_result = false;
10        for (int i = 0 ; i < input.length () ; i++)
11        {
12            if (input.charAt (i) == secondary)
13            {
14                contains_result = true;
15                break;
16            }
17        }
18        return contains_result;
19    }
20
21/*
22for two chars:
23*/
24public static boolean contains_dualchar (String main, String secondary)
25    {
26        boolean contains_result = false;
27        for (int i = 0 ; i < input.length () ; i++)
28        {
29            if (input.charAt (i) == secondary.charAt (0))
30            {
31                if (input.charAt (i + 1) == secondary.charAt (1))
32                {
33                    contains_result = true;
34                    break;
35                }
36            }
37        }
38        return contains_result;
39    }
40