Dado un número y su base, conviértelo a decimal. La base del número puede ser cualquier cosa tal que todos los dígitos se puedan representar usando del 0 al 9 y de la A a la Z. El valor de A es 10, el valor de B es 11 y así sucesivamente. Escribe una función para convertir el número a decimal.
Ejemplos:
Input number is given as string and output is an integer. Input: str = "1100", base = 2 Output: 12 Input: str = "11A", base = 16 Output: 282 Input: str = "123", base = 8 Output: 83
Le recomendamos encarecidamente que minimice su navegador y que pruebe esto usted mismo primero.
Siempre podemos usar la siguiente fórmula para convertir de cualquier base a decimal.
"str" is input number as a string "base" is the base of the input number. Decimal Equivalent is, 1*str[len-1] + base*str[len-2] + (base)2*str[len-3] + ...
A continuación se muestra la implementación de la fórmula anterior.
C++
// C++ program of th above approach
#include <bits/stdc++.h>
using namespace std;
// To return char for a value. For example '2'
// is returned for 2. 'A' is returned for 10. 'B'
// for 11
char reVal(int num)
{
if (num >= 0 && num <= 9)
return (char)(num + '0');
else
return (char)(num - 10 + 'A');
}
// Utility function to reverse a string
void strev(char *str)
{
int len = strlen(str);
int i;
for (i = 0; i < len/2; i++)
{
char temp = str[i];
str[i] = str[len-i-1];
str[len-i-1] = temp;
}
}
// Function to convert a given decimal number
// to a base 'base' and
char* fromDeci(char res[], int base, int inputNum)
{
int index = 0; // Initialize index of result
// Convert input number is given base by repeatedly
// dividing it by base and taking remainder
while (inputNum > 0)
{
res[index++] = reVal(inputNum % base);
inputNum /= base;
}
res[index] = '\0';
// Reverse the result
strev(res);
return res;
}
// Driver Code
int main()
{
int inputNum = 282, base = 16;
char res[100];
cout << "Equivalent of " << inputNum << "in base "<< base << "is " <<
fromDeci(res, base, inputNum);
return 0;
}
// This code is contributed by code_hunt.
C
// C program to convert a number from any base
// to decimal
#include <stdio.h>
#include <string.h>
// To return value of a char. For example, 2 is
// returned for '2'. 10 is returned for 'A', 11
// for 'B'
int val(char c)
{
if (c >= '0' && c <= '9')
return (int)c - '0';
else
return (int)c - 'A' + 10;
}
// Function to convert a number from given base 'b'
// to decimal
int toDeci(char *str, int base)
{
int len = strlen(str);
int power = 1; // Initialize power of base
int num = 0; // Initialize result
int i;
// Decimal equivalent is str[len-1]*1 +
// str[len-2]*base + str[len-3]*(base^2) + ...
for (i = len - 1; i >= 0; i--)
{
// A digit in input number must be
// less than number's base
if (val(str[i]) >= base)
{
printf("Invalid Number");
return -1;
}
num += val(str[i]) * power;
power = power * base;
}
return num;
}
// Driver code
int main()
{
char str[] = "11A";
int base = 16;
printf("Decimal equivalent of %s in base %d is "
" %d\n", str, base, toDeci(str, base));
return 0;
}
Java
// Java program to convert
// a number from any base
// to decimal
import java.io.*;
class GFG
{
// To return value of a char.
// For example, 2 is returned
// for '2'. 10 is returned
// for 'A', 11 for 'B'
static int val(char c)
{
if (c >= '0' && c <= '9')
return (int)c - '0';
else
return (int)c - 'A' + 10;
}
// Function to convert a
// number from given base
// 'b' to decimal
static int toDeci(String str,
int base)
{
int len = str.length();
int power = 1; // Initialize
// power of base
int num = 0; // Initialize result
int i;
// Decimal equivalent is
// str[len-1]*1 + str[len-2] *
// base + str[len-3]*(base^2) + ...
for (i = len - 1; i >= 0; i--)
{
// A digit in input number
// must be less than
// number's base
if (val(str.charAt(i)) >= base)
{
System.out.println("Invalid Number");
return -1;
}
num += val(str.charAt(i)) * power;
power = power * base;
}
return num;
}
// Driver code
public static void main (String[] args)
{
String str = "11A";
int base = 16;
System.out.println("Decimal equivalent of "+
str + " in base "+ base +
" is "+ " "+
toDeci(str, base));
}
}
// This code is contributed
// by anuj_67.
Python3
# Python program to convert a
# number from any base to decimal
# To return value of a char.
# For example, 2 is returned
# for '2'. 10 is returned for 'A',
# 11 for 'B'
def val(c):
if c >= '0' and c <= '9':
return ord(c) - ord('0')
else:
return ord(c) - ord('A') + 10;
# Function to convert a number
# from given base 'b' to decimal
def toDeci(str,base):
llen = len(str)
power = 1 #Initialize power of base
num = 0 #Initialize result
# Decimal equivalent is str[len-1]*1 +
# str[len-2]*base + str[len-3]*(base^2) + ...
for i in range(llen - 1, -1, -1):
# A digit in input number must
# be less than number's base
if val(str[i]) >= base:
print('Invalid Number')
return -1
num += val(str[i]) * power
power = power * base
return num
# Driver code
strr = "11A"
base = 16
print('Decimal equivalent of', strr,
'in base', base, 'is',
toDeci(strr, base))
# This code is contributed
# by Sahil shelangia
C#
// C# program to convert
// a number from any base
// to decimal
using System;
class GFG
{
// To return value of a char.
// For example, 2 is returned
// for '2'. 10 is returned
// for 'A', 11 for 'B'
static int val(char c)
{
if (c >= '0' && c <= '9')
return (int)c - '0';
else
return (int)c - 'A' + 10;
}
// Function to convert a
// number from given base
// 'b' to decimal
static int toDeci(string str,
int b_ase)
{
int len = str.Length;
int power = 1; // Initialize
// power of base
int num = 0; // Initialize result
int i;
// Decimal equivalent is
// str[len-1]*1 + str[len-2] *
// base + str[len-3]*(base^2) + ...
for (i = len - 1; i >= 0; i--)
{
// A digit in input number
// must be less than
// number's base
if (val(str[i]) >= b_ase)
{
Console.WriteLine("Invalid Number");
return -1;
}
num += val(str[i]) * power;
power = power * b_ase;
}
return num;
}
// Driver code
public static void Main ()
{
string str = "11A";
int b_ase = 16;
Console.WriteLine("Decimal equivalent of "+
str + " in base "+ b_ase +
" is " + toDeci(str, b_ase));
}
}
// This code is contributed
// by anuj_67.
PHP
<?php
// PHP program to convert a number from
// any base to decimal
// To return value of a char. For example,
// 2 is returned for '2'. 10 is returned
// for 'A', 11 for 'B'
function val($c)
{
if ($c >= '0' && $c <= '9')
return ord($c) - ord('0');
else
return ord($c) - ord('A') + 10;
}
// Function to convert a number from given
// base 'b' to decimal
function toDeci($str, $base)
{
$len = strlen($str);
$power = 1; // Initialize power of base
$num = 0; // Initialize result
// Decimal equivalent is str[len-1]*1 +
// str[len-2]*base + str[len-3]*(base^2) + ...
for ($i = $len - 1; $i >= 0; $i--)
{
// A digit in input number must be
// less than number's base
if (val($str[$i]) >= $base)
{
print("Invalid Number");
return -1;
}
$num += val($str[$i]) * $power;
$power = $power * $base;
}
return $num;
}
// Driver code
$str = "11A";
$base = 16;
print("Decimal equivalent of $str " .
"in base $base is " . toDeci($str, $base));
// This code is contributed by mits
?>
Javascript
<script>
// Javascript program to convert
// a number from any base
// to decimal
// To return value of a char.
// For example, 2 is returned
// for '2'. 10 is returned
// for 'A', 11 for 'B'
function val(c)
{
if (c >= '0'.charCodeAt() &&
c <= '9'.charCodeAt())
return (c - '0'.charCodeAt());
else
return (c - 'A'.charCodeAt() + 10);
}
// Function to convert a
// number from given base
// 'b' to decimal
function toDeci(str, b_ase)
{
let len = str.length;
// Initialize
// power of base
let power = 1;
// Initialize result
let num = 0;
let i;
// Decimal equivalent is
// str[len-1]*1 + str[len-2] *
// base + str[len-3]*(base^2) + ...
for(i = len - 1; i >= 0; i--)
{
// A digit in input number
// must be less than
// number's base
if (val(str[i].charCodeAt()) >= b_ase)
{
document.write("Invalid Number");
return -1;
}
num += val(str[i].charCodeAt()) * power;
power = power * b_ase;
}
return num;
}
// Driver code
let str = "11A";
let b_ase = 16;
document.write("Decimal equivalent of "+
str + " in base "+ b_ase +
" is " + toDeci(str, b_ase));
// This code is contributed by divyesh072019
</script>
Producción :
Decimal equivalent of 11A in base 16 is 282
Complejidad de tiempo: O(N) n representa la longitud de la string
Complejidad espacial : O(1)
¿Cómo hacer al revés?
Deje que el número decimal de entrada dado sea «inputNum» y la base de destino sea «base». Dividimos repetidamente inputNum por base y almacenamos el resto. Finalmente invertimos la string obtenida. A continuación se muestra la implementación de C.
C++
// C++ Program to convert decimal to any given base
#include <bits/stdc++.h>
using namespace std;
// To return char for a value. For example '2'
// is returned for 2. 'A' is returned for 10. 'B'
// for 11
char reVal(int num)
{
if (num >= 0 && num <= 9)
return (char)(num + '0');
else
return (char)(num - 10 + 'A');
}
// Function to convert a given decimal number
// to a base 'base' and
string fromDeci(string& res, int base, int inputNum)
{
int index = 0; // Initialize index of result
// Convert input number is given base by repeatedly
// dividing it by base and taking remainder
while (inputNum > 0) {
res.push_back(reVal(inputNum % base));
index++;
inputNum /= base;
}
// Reverse the result
reverse(res.begin(), res.end());
return res;
}
// Driver program
int main()
{
int inputNum = 282, base = 16;
string res;
cout << "Equivalent of " << inputNum << " in base "
<< base << " is " << fromDeci(res, base, inputNum)
<< endl;
return 0;
}
// The code is contributed by Gautam goel (gautamgoel962)
C
// C Program to convert decimal to any given base
#include <stdio.h>
#include <string.h>
// To return char for a value. For example '2'
// is returned for 2. 'A' is returned for 10. 'B'
// for 11
char reVal(int num)
{
if (num >= 0 && num <= 9)
return (char)(num + '0');
else
return (char)(num - 10 + 'A');
}
// Utility function to reverse a string
void strev(char *str)
{
int len = strlen(str);
int i;
for (i = 0; i < len/2; i++)
{
char temp = str[i];
str[i] = str[len-i-1];
str[len-i-1] = temp;
}
}
// Function to convert a given decimal number
// to a base 'base' and
char* fromDeci(char res[], int base, int inputNum)
{
int index = 0; // Initialize index of result
// Convert input number is given base by repeatedly
// dividing it by base and taking remainder
while (inputNum > 0)
{
res[index++] = reVal(inputNum % base);
inputNum /= base;
}
res[index] = '\0';
// Reverse the result
strev(res);
return res;
}
// Driver program
int main()
{
int inputNum = 282, base = 16;
char res[100];
printf("Equivalent of %d in base %d is "
" %s\n", inputNum, base, fromDeci(res, base, inputNum));
return 0;
}
Java
// Java Program to convert decimal to any given base
import java.lang.*;
import java.io.*;
import java.util.*;
class GFG
{
// To return char for a value. For
// example '2' is returned for 2.
// 'A' is returned for 10. 'B' for 11
static char reVal(int num)
{
if (num >= 0 && num <= 9)
return (char)(num + 48);
else
return (char)(num - 10 + 65);
}
// Function to convert a given decimal number
// to a base 'base' and
static String fromDeci(int base1, int inputNum)
{
String s = "";
// Convert input number is given
// base by repeatedly dividing it
// by base and taking remainder
while (inputNum > 0)
{
s += reVal(inputNum % base1);
inputNum /= base1;
}
StringBuilder ix = new StringBuilder();
// append a string into StringBuilder input1
ix.append(s);
// Reverse the result
return new String(ix.reverse());
}
// Driver code
public static void main (String[] args)
{
int inputNum = 282, base1 = 16;
System.out.println("Equivalent of " + inputNum +
" in base "+base1+" is " +
fromDeci(base1, inputNum));
}
}
// This code is contributed by mits
Python3
# Python3 Program to convert decimal to
# any given base
# To return char for a value. For example
# '2' is returned for 2. 'A' is returned
# for 10. 'B' for 11
def reVal(num):
if (num >= 0 and num <= 9):
return chr(num + ord('0'));
else:
return chr(num - 10 + ord('A'));
# Utility function to reverse a string
def strev(str):
len = len(str);
for i in range(int(len / 2)):
temp = str[i];
str[i] = str[len - i - 1];
str[len - i - 1] = temp;
# Function to convert a given decimal
# number to a base 'base' and
def fromDeci(res, base, inputNum):
index = 0; # Initialize index of result
# Convert input number is given base
# by repeatedly dividing it by base
# and taking remainder
while (inputNum > 0):
res+= reVal(inputNum % base);
inputNum = int(inputNum / base);
# Reverse the result
res = res[::-1];
return res;
# Driver Code
inputNum = 282;
base = 16;
res = "";
print("Equivalent of", inputNum, "in base",
base, "is", fromDeci(res, base, inputNum));
# This code is contributed by mits
C#
// C# Program to convert decimal to any given base
using System;
using System.Collections;
class GFG
{
// To return char for a value. For
// example '2' is returned for 2.
// 'A' is returned for 10. 'B' for 11
static char reVal(int num)
{
if (num >= 0 && num <= 9)
return (char)(num + 48);
else
return (char)(num - 10 + 65);
}
// Function to convert a given decimal number
// to a base 'base' and
static string fromDeci(int base1, int inputNum)
{
string s = "";
// Convert input number is given
// base by repeatedly dividing it
// by base and taking remainder
while (inputNum > 0)
{
s += reVal(inputNum % base1);
inputNum /= base1;
}
char[] res = s.ToCharArray();
// Reverse the result
Array.Reverse(res);
return new String(res);
}
// Driver code
static void Main()
{
int inputNum = 282, base1 = 16;
Console.WriteLine("Equivalent of " + inputNum +
" in base "+base1+" is " +
fromDeci(base1, inputNum));
}
}
// This code is contributed by mits
PHP
<?php
// PHP Program to convert decimal to
// any given base
// To return char for a value. For example '2'
// is returned for 2. 'A' is returned for 10.
// 'B' for 11
function reVal($num)
{
if ($num >= 0 && $num <= 9)
return chr($num + ord('0'));
else
return chr($num - 10 + ord('A'));
}
// Utility function to reverse a string
function strev($str)
{
$len = strlen($str);
for ($i = 0; $i < $len / 2; $i++)
{
$temp = $str[$i];
$str[$i] = $str[$len - $i - 1];
$str[$len - $i - 1] = $temp;
}
}
// Function to convert a given decimal
// number to a base 'base' and
function fromDeci($res, $base, $inputNum)
{
$index = 0; // Initialize index of result
// Convert input number is given base
// by repeatedly dividing it by base
// and taking remainder
while ($inputNum > 0)
{
$res.= reVal($inputNum % $base);
$inputNum = (int)($inputNum / $base);
}
// Reverse the result
$res = strrev($res);
return $res;
}
// Driver Code
$inputNum = 282;
$base = 16;
$res = "";
print("Equivalent of $inputNum in base $base is " .
fromDeci($res, $base, $inputNum));
// This code is contributed by mits
?>
Javascript
<script>
// Javascript Program to convert decimal to any given base
// To return char for a value. For
// example '2' is returned for 2.
// 'A' is returned for 10. 'B' for 11
function reVal(num)
{
if (num >= 0 && num <= 9)
return String.fromCharCode(num + 48);
else
return String.fromCharCode(num - 10 + 65);
}
// Function to convert a given decimal number
// to a base 'base' and
function fromDeci(base1, inputNum)
{
let s = "";
// Convert input number is given
// base by repeatedly dividing it
// by base and taking remainder
while (inputNum > 0)
{
s += reVal(inputNum % base1);
inputNum = parseInt(inputNum / base1, 10);
}
let res = s.split('');
// Reverse the result
res.reverse();
return res.join("");
}
let inputNum = 282, base1 = 16;
document.write("Equivalent of " + inputNum +
" in base "+base1+" is " +
fromDeci(base1, inputNum));
// This code is contributed by rameshtravel07.
</script>
Producción :
Equivalent of 282 in base 16 is 11A
Complejidad de tiempo: O (N) El número de entrada de conversión se basa en inputNum repetidamente dividiéndolo por la base y tomando el resto toma O (n) complejidad
Espacio Auxiliar : O(1)
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Publicación traducida automáticamente
Artículo escrito por GeeksforGeeks-1 y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA