Java BigInteger toString()用法及代碼示例

BigInteger類為toString()提供2種方法。

• toString(int radix)：java.math.BigInteger.toString(int radix)方法以給定的基數返回此BigInteger的十進製String表示形式。基數參數決定應返回字符串的基數(二進製，八進製，十六進製等)。對於toString()，基數默認為10。如果基數在Character.MIN_RADIX到Character.MAX_RADIX(包括這兩個字符)的範圍之外，則默認為10。

  用法:

  public String toString(int radix)

  參數：此方法接受單個強製性參數基數，該基數是String表示形式的基數。

  
  

  返回值：此方法以給定的基數返回此BigInteger的十進製String表示形式。

  例子：

  Input: BigInteger1=321456 radix =2
  Output: 1001110011110110000
  Explanation: BigInteger1.toString(2)=1001110011110110000. 
  when radix is 2 then function will first convert the BigInteger 
  to binary form then it will return String representation of that binary number.
  
  Input: BigInteger1=321456 radix=16
  Output: 4e7b0
  Explanation: BigInteger1.toString()=4e7b0. 
  when radix is 16 then function will first convert the BigInteger 
  to hexadecimal form then it will return String representation of that hexadecimal number.
  

  以下示例程序旨在說明BigInteger類的toString(int radix)方法：

  示例1:當radix = 2時。表示二進製形式的字符串。

  // Java program to demonstrate 
  // toString(radix) method of BigInteger 
    
  import java.math.BigInteger; 
    
  public class GFG { 
    
      public static void main(String[] args) 
      { 
    
          // Creating BigInteger object 
          BigInteger b1; 
          b1 = new BigInteger("321456"); 
    
          // create radix 
          int radix = 2; 
    
          // apply toString(radix) method 
          String b1String = b1.toString(radix); 
    
          // print String 
          System.out.println("Binary String of BigInteger "
                             + b1 + " is equal to " + b1String); 
      } 
  }

  輸出：

  Binary String of BigInteger 321456 is equal to 1001110011110110000
  

  示例2:當radix = 8表示八進製形式字符串

  // Java program to demonstrate  
  // toString(radix) method of BigInteger 
    
  import java.math.BigInteger; 
    
  public class GFG { 
    
      public static void main(String[] args) 
      { 
    
          // Creating BigInteger object 
          BigInteger b1; 
          b1 = new BigInteger("34567876543"); 
    
          // create radix 
          int radix = 8; 
    
          // apply toString(radix) method 
          String b1String = b1.toString(radix); 
    
          // print String 
          System.out.println("Octal String of BigInteger "
                            + b1 + " is equal to " + b1String); 
      } 
  }

  輸出：

  Octal String of BigInteger 34567876543 is equal to 401431767677
  

  示例3:當radix = 16時表示十六進製十進製形式的字符串

  // Java program to demonstrate toString(radix) method of BigInteger 
    
  import java.math.BigInteger; 
    
  public class GFG { 
    
      public static void main(String[] args) 
      { 
    
          // Creating BigInteger object 
          BigInteger b1; 
          b1 = new BigInteger("8765432123456"); 
    
          // create radix 
          int radix = 16; 
    
          // apply toString(radix) method 
          String b1String = b1.toString(radix); 
    
          // print String 
          System.out.println("Hexadecimal String of BigInteger "
                             + b1 + " is equal to " + b1String); 
      } 
  }

  輸出：

  Hexadecimal String of BigInteger 8765432123456 is equal to 7f8dc77d040
  



• toString()：java.math.BigInteger.toString()方法返回此BigInteger的十進製String表示形式。此方法對於將BigInteger轉換為String很有用。在BigInteger上應用toString()之後，可以在BigInteger上應用所有字符串操作。

  用法:

  public String toString()

  返回值：此方法返回此BigInteger的十進製String表示形式。

  例子：

  Input: BigInteger1=321456 
  Output: 321456
  Explanation: BigInteger1.toString()=321456. 
  The answer is the String representation of BigInteger
  
  Input: BigInteger1=59185482345
  Output: 59185482345
  Explanation: BigInteger1.toString()=59185482345. 
  The answer is the String representation of BigInteger
  

  下麵的程序說明BigInteger類的toString()方法：

  例：

  // Java program to demonstrate toString() method of BigInteger 
    
  import java.math.BigInteger; 
    
  public class GFG { 
    
      public static void main(String[] args) 
      { 
    
          // Creating 2 BigInteger objects 
          BigInteger b1, b2; 
          b1 = new BigInteger("35152194853456789"); 
    
          // apply toString() method 
          String b1String = b1.toString(); 
    
          // print String 
          System.out.println(b1String); 
    
          b2 = new BigInteger("7654323234565432345676543234567"); 
    
          // apply toString() method 
          String b2String = b2.toString(); 
    
          // print String 
          System.out.println(b2String); 
      } 
  }

  輸出：

  35152194853456789
  7654323234565432345676543234567
  

參考： https://docs.oracle.com/javase/7/docs/api/java/math/BigInteger.html#toString(java.math.BigInteger)