計算字符串中的字符

Question

我是Java新手，我想知道如何計算字符串Hello中的l s的數量？ 任何幫助將非常感激。

public int countChar(String s, char c) 
{ 
    String st= s; 
    char ch =c; 
    int counter = 0; 
    for(int i=0; i<st.length(); i++) 
    { 
     if(st.charAt(i) == ch) 
     { 
      counter++; 
     } 
    }  
    return counter; 
} 

public static void main(String[] args) 
{ 
    new Loop().countChar("Hello", 'l');   
} 

Answer 1

這應該是您正常工作 - 如果你想打印結果，改變main這樣：

public static void main(String[] args) 
{ 
    int count = new Loop().countChar("Hello", 'l'); 
    System.out.println("The count is: " + count); 
} 

Answer 2

嘗試用下面的代碼：

公共類CharacterCout {

public static int getCharacterCount(String string, char character) { 
    int counter = 0; 
    for(int i=0;i<string.length();i++) { 
     if(string.charAt(i)==character){ 
      counter++; 
     } 
    } 
    return counter; 
} 

public static void main(String[] args) { 
    String string = "Hello World!"; 
    char character = 'l'; 
    System.out.println("Character "+character+" count: " +getCharacterCount(string, character)); 
} 

}

Answer 3

public String twoOccurrences(String stringa, char stringb) { 
    int counter = 0; 
    for (int i = 0; i < stringa.length(); i++) { 
     if (stringa.charAt(i) == stringb) { 
      counter++; 
     } 
    } 
    if (counter >= 1) { 
     return "" + counter; 
    } else { 
     return "There is no matching letters"; 
    } 
} 

public void testOcurrences() { 
    char stringb = 'a'; 
    String stringa = "Banana"; 
    System.out.println("String a is :" + stringa); 
    System.out.println("String b is :" + stringb); 
    String occurrence = twoOccurrences(stringa, stringb); 
    System.out.println("There is " + occurrence + " '" + stringb + "' in " + stringa); 
} 

}