Java Integer toOctalString()用法及代码示例

八进制是以8为底的数字系统，在操作中使用数字0到7。八进制被广泛用于PDP-8等系统的计算中，IBM大型机采用12位，24位或36位字。
Java.lang.Integer.toOctalString()方法是Java中的内置函数，用于将整数参数的字符串表示形式作为基数8中的无符号整数返回。

用法:

public static String toOctalString(int num)

参数：该方法接受整数类型的单个参数num，要求将其转换为字符串。

返回值：该函数将整数参数的字符串表示形式返回为以8为底的无符号整数。

例子：

 Consider an integer a = 86
 Octal output = 126

Consider an integer a = 186 
Octal output = 272        

以下示例程序旨在说明Integer.toOctalString()方法的用法：
程序1:对于正整数：

// Java program to demonstrate working 
// of Integer.toOctalString() method 
  
import java.lang.*; 
  
public class Geeks { 
  
    public static void main(String[] args) 
    { 
  
        int a = 527; 
        System.out.println("Integral Number = " + a); 
  
        // returns the string representation of the unsigned int value 
        // represented by the argument in octal (base 8) 
        System.out.println("Octal Number = " + Integer.toOctalString(a)); 
    } 
}

Integral Number = 527
Octal Number = 1017

程序2:对于负整数：

// Java program to demonstrate working 
// of Integer.toOctalString() method 
  
import java.lang.*; 
  
public class Geeks { 
  
    public static void main(String[] args) 
    { 
  
        int a = -51; 
        System.out.println("Integral Number = " + a); 
  
        // Returns the string representation of the unsigned int value 
        // in octal (base 8) 
        System.out.println("Octal Number = " + Integer.toOctalString(a)); 
    } 
}

Integral Number = -51
Octal Number = 37777777715

程序3:对于十进制值或字符串：
注意：每当将十进制数字或字符串作为参数传递时，它都会返回一条错误消息，导致类型不兼容。

// Java program to demonstrate working 
// of Integer.toOctalString() method 
  
import java.lang.*; 
  
public class Geeks { 
  
    public static void main(String[] args) 
    { 
  
        double a = 18.71; 
  
        // Returns the string representation of the unsigned int value 
        // in octal (base 8) 
        System.out.println("Octal output = " + Integer.toOctalString(a)); 
  
        String b = "63"; 
  
        // Returns the string representation of the unsigned int value 
        // in octal (base 8) 
        System.out.println("Octal output = " + Integer.toOctalString(a)); 
    } 
}

输出：

prog.java:15:error:incompatible types:possible lossy conversion from double to int
        System.out.println("Octal output = " + Integer.toOctalString(a));
                                                                     ^
prog.java:21:error:incompatible types:possible lossy conversion from double to int
        System.out.println("Octal output = " + Integer.toOctalString(a));
                                                                     ^
Note:Some messages have been simplified; recompile with -Xdiags:verbose to get full output
2 errors