给定十六进制数，任务是将其转换为八进制数。
例子：
Input: Hexadecimal = 1AC
Output: Binary = 0654
Explanation:
Equivalent binary value of 1: 0001
Equivalent binary value of A: 1010
Equivalent binary value of C: 1100
Grouping in terms of 3: 000 110 101 100
Equivalent octal value of 000: 0
Equivalent octal value of 110: 6
Equivalent octal value of 101: 5
Equivalent octal value of 100: 4
Input: Hexadecimal = 5D1F
Output: Octal = 56437
方法：
十六进制数字是位置数字系统，其基数或基数为16，并使用十六个不同的符号。
八进制数或简称oct是8的底数，并使用数字0到7。可以通过将连续的二进制数字分组为三组(从右开始)来由二进制数字组成八进制数字。
转换步骤
- 为给定十六进制数字的每个数字找到等效的二进制数字。如果任何二进制等效项短于4位，则在左侧添加0。
- 将二进制数字分成几组，每组从右到左包含3位或数字。如果最后一组的位数少于3位，则在左侧添加0。
- 查找每个二进制组的八进制等效项。
下面是上述方法的实现：
C++
// C++ program to convert
// Hexadecimal to Octal
#include
using namespace std;
// Function to convert HexaDecimal to Binary
long long int hex_to_bin(char hex[])
{
long long int bin, place;
int i = 0, rem, val;
bin = 0ll;
place = 0ll;
// Hexadecimal to binary conversion
for (i = 0; hex[i] != '\0'; i++) {
bin = bin * place;
switch (hex[i]) {
case '0':
bin += 0;
break;
case '1':
bin += 1;
break;
case '2':
bin += 10;
break;
case '3':
bin += 11;
break;
case '4':
bin += 100;
break;
case '5':
bin += 101;
break;
case '6':
bin += 110;
break;
case '7':
bin += 111;
break;
case '8':
bin += 1000;
break;
case '9':
bin += 1001;
break;
case 'a':
case 'A':
bin += 1010;
break;
case 'b':
case 'B':
bin += 1011;
break;
case 'c':
case 'C':
bin += 1100;
break;
case 'd':
case 'D':
bin += 1101;
break;
case 'e':
case 'E':
bin += 1110;
break;
case 'f':
case 'F':
bin += 1111;
break;
default:
cout << "Invalid hexadecimal input.";
}
place = 10000;
}
return bin;
}
// Function to convert Binary to Octal
long long int bin_to_oct(long long bin)
{
long long int octal, place;
int i = 0, rem, val;
octal = 0ll;
place = 0ll;
place = 1;
// Binary to octal conversion
while (bin > 0) {
rem = bin % 1000;
switch (rem) {
case 0:
val = 0;
break;
case 1:
val = 1;
break;
case 10:
val = 2;
break;
case 11:
val = 3;
break;
case 100:
val = 4;
break;
case 101:
val = 5;
break;
case 110:
val = 6;
break;
case 111:
val = 7;
break;
}
octal = (val * place) + octal;
bin /= 1000;
place *= 10;
}
return octal;
}
// Function to Convert
// Hexadecimal Number to Octal Number
long long int hex_to_oct(char hex[])
{
long long int octal, bin;
// convert HexaDecimal to Binary
bin = hex_to_bin(hex);
// convert Binary to Octal
octal = bin_to_oct(bin);
return octal;
}
// driver code
int main()
{
// Get the hexadecimal number
char hex[20] = "1AC";
// convert hexadecimal to octal
cout << "Equivalent Octal Value = " << hex_to_oct(hex);
return 0;
}
//This code is contributed by shubhamsingh10 C
// C program to convert
// Hexadecimal to Octal
#include
#include
#include
// Function to convert HexaDecimal to Binary
long long int hex_to_bin(char hex[])
{
long long int bin, place;
int i = 0, rem, val;
bin = 0ll;
place = 0ll;
// Hexadecimal to binary conversion
for (i = 0; hex[i] != '\0'; i++) {
bin = bin * place;
switch (hex[i]) {
case '0':
bin += 0;
break;
case '1':
bin += 1;
break;
case '2':
bin += 10;
break;
case '3':
bin += 11;
break;
case '4':
bin += 100;
break;
case '5':
bin += 101;
break;
case '6':
bin += 110;
break;
case '7':
bin += 111;
break;
case '8':
bin += 1000;
break;
case '9':
bin += 1001;
break;
case 'a':
case 'A':
bin += 1010;
break;
case 'b':
case 'B':
bin += 1011;
break;
case 'c':
case 'C':
bin += 1100;
break;
case 'd':
case 'D':
bin += 1101;
break;
case 'e':
case 'E':
bin += 1110;
break;
case 'f':
case 'F':
bin += 1111;
break;
default:
printf("Invalid hexadecimal input.");
}
place = 10000;
}
return bin;
}
// Function to convert Binary to Octal
long long int bin_to_oct(long long bin)
{
long long int octal, place;
int i = 0, rem, val;
octal = 0ll;
place = 0ll;
place = 1;
// Binary to octal conversion
while (bin > 0) {
rem = bin % 1000;
switch (rem) {
case 0:
val = 0;
break;
case 1:
val = 1;
break;
case 10:
val = 2;
break;
case 11:
val = 3;
break;
case 100:
val = 4;
break;
case 101:
val = 5;
break;
case 110:
val = 6;
break;
case 111:
val = 7;
break;
}
octal = (val * place) + octal;
bin /= 1000;
place *= 10;
}
return octal;
}
// Function to Convert
// Hexadecimal Number to Octal Number
long long int hex_to_oct(char hex[])
{
long long int octal, bin;
// convert HexaDecimal to Binary
bin = hex_to_bin(hex);
// convert Binary to Octal
octal = bin_to_oct(bin);
return octal;
}
// driver code
int main()
{
// Get the hexadecimal number
char hex[20] = "1AC";
// convert hexadecimal to octal
printf("Equivalent Octal Value = %lld",
hex_to_oct(hex));
return 0;
} Java
// Java program to convert
// Hexadecimal to Octal
class hex_to_oct
{
// declaring main method.
public static void main(String[] args)
{
int dec = 0;
// taking 1AC as an example of hexadecimal Number.
String hexa = "1AC";
int c = hexa.length() - 1;
// finding the decimal equivalent of the
// hexa decimal number
for(int i = 0; i < hexa.length() ; i ++ )
{
//extracting each character from the string.
char ch = hexa.charAt(i);
switch (ch)
{
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
dec = dec + Integer.parseInt(Character.toString(ch))*
(int)Math.pow(16,c);
c--;
break;
case 'a':
case 'A':
dec = dec + 10 * (int)Math.pow(16, c);
c--;
break;
case 'b':
case 'B':
dec = dec + 11 * (int)Math.pow(16, c);
c--;
break;
case 'c':
case 'C':
dec = dec + 12 * (int)Math.pow(16, c);
c--;
break;
case 'd':
case 'D':
dec = dec + 13 * (int)Math.pow(16, c);
c--;
break;
case 'e':
case 'E':
dec = dec + 14 * (int)Math.pow(16, c);
c--;
break;
case 'f':
case 'F':
dec = dec + 15 * (int)Math.pow(16, c);
c--;
break;
default:
System.out.println("Invalid hexa input");
break;
}
}
// String oct to store the octal equivalent of a hexadecimal number.
String oct ="";
//converting decimal to octal number.
while(dec > 0)
{
oct = dec % 8 + oct;
dec = dec / 8;
}
// Printing the final output.
System.out.println("Equivalent Octal Value = "+oct);
}
}
// This code is contributed by Animesh_GuptaPython
# importing math package
import math
hex = "1AC"
# variable oct to store
# octal equivalent of hexa decimal
# number returned from the method
oct = ""
dec = i = 0
c = len(hex) - 1
# loop to extract each digit of number
while i < len(hex):
# digit extracted
d = hex[i]
if d == '0' or d == '1' or d == '2' or \
d == '3' or d == '4' or d == '5':
dec = dec + int(d) * int(math.pow(16, c))
elif d == '6' or d == '7' or d == '8' or d == '9':
dec = dec + int(d) * int(math.pow(16, c))
elif (d == 'A') or (d == 'a'):
dec = dec + 10 * int(math.pow(16, c))
elif (d == 'B') or (d == 'b'):
dec = dec + 11 * int(math.pow(16, c))
elif (d == 'C') or (d == 'c'):
dec = dec + 12 * int(math.pow(16, c))
elif (d == 'D') or (d == 'd'):
dec = dec + 13 * int(math.pow(16, c))
elif (d == 'E') or (d == 'e'):
dec = dec + 14 * int(math.pow(16, c))
elif (d == 'F') or (d == 'f'):
dec = dec + 15 * int(math.pow(16, c))
else:
print("invalid input")
break
i+= 1
c -= 1
# loop to find octal equivalent
# stored in dec i.e.
# conversion of decimal to octal.
while (dec > 0):
oct = "".join([str(int(dec % 8)) , oct])
dec = int(dec / 8)
# printing the final result
print("Equivalent Octal Value =",oct)
# This code is contributed by 29AjayKumarC#
// C# program to convert
// Hexadecimal to Octal
using System;
class GFG{
// Driver code
public static void Main(string[] args)
{
int dec = 0;
// taking 1AC as an example
// of hexadecimal Number.
string hexa = "1AC";
int c = hexa.Length - 1;
// Finding the decimal
// equivalent of the
// hexa decimal number
for(int i = 0; i < hexa.Length ; i ++ )
{
// Extracting each character
// from the string.
char ch = hexa[i];
switch (ch)
{
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
dec = dec + Int32.Parse(ch.ToString())*
(int)Math.Pow(16, c);
c--;
break;
case 'a':
case 'A':
dec = dec + 10 * (int)Math.Pow(16, c);
c--;
break;
case 'b':
case 'B':
dec = dec + 11 * (int)Math.Pow(16, c);
c--;
break;
case 'c':
case 'C':
dec = dec + 12 * (int)Math.Pow(16, c);
c--;
break;
case 'd':
case 'D':
dec = dec + 13 * (int)Math.Pow(16, c);
c--;
break;
case 'e':
case 'E':
dec = dec + 14 * (int)Math.Pow(16, c);
c--;
break;
case 'f':
case 'F':
dec = dec + 15 * (int)Math.Pow(16, c);
c--;
break;
default:
Console.Write("Invalid hexa input");
break;
}
}
// String oct to store the octal
// equivalent of a hexadecimal number.
string oct = "";
// converting decimal
// to octal number.
while(dec > 0)
{
oct = dec % 8 + oct;
dec = dec / 8;
}
// Printing the final output.
Console.Write("Equivalent Octal Value = " +
oct);
}
}
// This code is contributed by rutvik_56输出 ：
Equivalent Octal Value = 654
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