Dada una string, cuenta el número de palabras que contiene. Las palabras están separadas por los siguientes caracteres: espacio (‘ ‘) o nueva línea (‘\n’) o tabulación (‘\t’) o una combinación de estos.
Puede haber muchas soluciones a este problema. La siguiente es una solución simple e interesante.
La idea es mantener dos estados: IN y OUT. El estado OUT indica que se ve un separador. El estado IN indica que se ve un carácter de palabra. Incrementamos el conteo de palabras cuando el estado anterior es FUERA y el siguiente carácter es un carácter de palabra.
C++
/* C++ program to count no of words
from given input string. */
#include <bits/stdc++.h>
using namespace std;
#define OUT 0
#define IN 1
// returns number of words in str
unsigned countWords(char *str)
{
int state = OUT;
unsigned wc = 0; // word count
// Scan all characters one by one
while (*str)
{
// If next character is a separator, set the
// state as OUT
if (*str == ' ' || *str == '\n' || *str == '\t')
state = OUT;
// If next character is not a word separator and
// state is OUT, then set the state as IN and
// increment word count
else if (state == OUT)
{
state = IN;
++wc;
}
// Move to next character
++str;
}
return wc;
}
// Driver code
int main(void)
{
char str[] = "One two three\n four\tfive ";
cout<<"No of words : "<<countWords(str);
return 0;
}
// This is code is contributed by rathbhupendra
C
/* C program to count no of words from given input string. */
#include <stdio.h>
#define OUT 0
#define IN 1
// returns number of words in str
unsigned countWords(char *str)
{
int state = OUT;
unsigned wc = 0; // word count
// Scan all characters one by one
while (*str)
{
// If next character is a separator, set the
// state as OUT
if (*str == ' ' || *str == '\n' || *str == '\t')
state = OUT;
// If next character is not a word separator and
// state is OUT, then set the state as IN and
// increment word count
else if (state == OUT)
{
state = IN;
++wc;
}
// Move to next character
++str;
}
return wc;
}
// Driver program to tes above functions
int main(void)
{
char str[] = "One two three\n four\tfive ";
printf("No of words : %u", countWords(str));
return 0;
}
Java
/* Java program to count no of words
from given input string. */
public class GFG {
static final int OUT = 0;
static final int IN = 1;
// returns number of words in str
static int countWords(String str)
{
int state = OUT;
int wc = 0; // word count
int i = 0;
// Scan all characters one by one
while (i < str.length())
{
// If next character is a separator, set the
// state as OUT
if (str.charAt(i) == ' ' || str.charAt(i) == '\n'
|| str.charAt(i) == '\t')
state = OUT;
// If next character is not a word separator
// and state is OUT, then set the state as IN
// and increment word count
else if (state == OUT)
{
state = IN;
++wc;
}
// Move to next character
++i;
}
return wc;
}
// Driver program to test above functions
public static void main(String args[])
{
String str = "One two three\n four\tfive ";
System.out.println("No of words : " + countWords(str));
}
}
// This code is contributed by Sumit Ghosh
Python3
# Python3 program to count words
# in a given string
OUT = 0
IN = 1
# Returns number of words in string
def countWords(string):
state = OUT
wc = 0
# Scan all characters one by one
for i in range(len(string)):
# If next character is a separator,
# set the state as OUT
if (string[i] == ' ' or string[i] == '\n' or
string[i] == '\t'):
state = OUT
# If next character is not a word
# separator and state is OUT, then
# set the state as IN and increment
# word count
elif state == OUT:
state = IN
wc += 1
# Return the number of words
return wc
# Driver Code
string = "One two three\n four\tfive "
print("No. of words : " + str(countWords(string)))
# This code is contributed by BHAVYA JAIN
C#
// C# program to count no of words
// from given input string.
using System;
class GFG {
static int OUT = 0;
static int IN = 1;
// returns number of words in str
static int countWords(String str)
{
int state = OUT;
int wc = 0; // word count
int i = 0;
// Scan all characters one
// by one
while (i < str.Length)
{
// If next character is a separator,
// set the state as OUT
if (str[i] == ' ' || str[i] == '\n'||
str[i] == '\t')
state = OUT;
// If next character is not a word
// separator and state is OUT, then
// set the state as IN and increment
// word count
else if (state == OUT)
{
state = IN;
++wc;
}
// Move to next character
++i;
}
return wc;
}
// Driver program to test above functions
public static void Main()
{
String str = "One two three\n four\tfive ";
Console.WriteLine("No of words : "
+ countWords(str));
}
}
// This code is contributed by Sam007.
PHP
<?php
// PHP program to count no of
// words from given input string
$OUT = 0;
$IN = 1;
// returns number of words in str
function countWords($str)
{
global $OUT, $IN;
$state = $OUT;
$wc = 0; // word count
$i = 0;
// Scan all characters one by one
while ($i < strlen($str))
{
// If next character is
// a separator, set the
// state as OUT
if ($str[$i] == " " ||
$str[$i] == "\n" ||
$str[$i] == "\t")
$state = $OUT;
// If next character is not a
// word separator and state is
// OUT, then set the state as
// IN and increment word count
else if ($state == $OUT)
{
$state = $IN;
++$wc;
}
// Move to next character
++$i;
}
return $wc;
}
// Driver Code
$str = "One two three\n four\tfive ";
echo "No of words : " . countWords($str);
// This code is contributed
// by ChitraNayal
?>
Javascript
<script>
// javascript program to count no of words
// from given input string.
var OUT = 0;
var IN = 1;
// returns number of words in str
function countWords( str)
{
var state = OUT;
var wc = 0; // word count
var i = 0;
// Scan all characters one
// by one
while (i < str.length)
{
// If next character is a separator,
// set the state as OUT
if (str[i] == ' ' || str[i] == '\n'||
str[i] == '\t')
state = OUT;
// If next character is not a word
// separator and state is OUT, then
// set the state as IN and increment
// word count
else if (state == OUT)
{
state = IN;
++wc;
}
// Move to next character
++i;
}
return wc;
}
// Driver program to test above functions
var str = "One two three\n four\tfive ";
document.write("No of words : "
+ countWords(str));
// This code is contributed by bunnyram19.
</script>
Java
// Java program to count total
// number of words in the string
class GFG
{
// Function to count total number
// of words in the string
public static int
countWords(String str)
{
// Check if the string is null
// or empty then return zero
if (str == null || str.isEmpty())
return 0;
// Splitting the string around
// matches of the given regular
// expression
String[] words = str.split("\\s+");
// Return number of words
// in the given string
return words.length;
}
// Driver Code
public static void main(String args[])
{
// Given String str
String str =
"One two three\n four\tfive ";
// Print the result
System.out.println("No of words : " +
countWords(str));
}
}
// This code is contributed by Prashant Srivastava
Python3
# Python program to count total
# number of words in the string
def countWords(s):
# Check if the string is null
# or empty then return zero
if s.strip() == "":
return 0
# Splitting the string
words = s.split()
return len(words)
if __name__ == "__main__":
s = "One two three\n four\tfive "
print("No of words : ", countWords(s))
Java
// Java program to count total
// number of words in the string
import java.util.StringTokenizer;
class GFG
{
// Function to count total number
// of words in the string
public static int
countWords(String str)
{
// Check if the string is null
// or empty then return zero
if (str == null || str.isEmpty())
return 0;
// Create a StringTokenizer with the
// given string passed as a parameter
StringTokenizer tokens = new
StringTokenizer(str);
// Return the number of words
// in the given string using
// countTokens() method
return tokens.countTokens();
}
// Driver Code
public static void main(String args[])
{
// Given String str
String str =
"One two three\n four\tfive ";
// Print the result
System.out.println("No of words: " +
countWords(str));
}
}
// This code is contributed by Prashant Srivastava
C++
// C++ program to count total
// number of words in the string
#include <bits/stdc++.h>
using namespace std;
// Function to count total number
// of words in the string
int countWords(char* str, int n)
{
// Check if the string is null
// or empty then return zero
if (n == 0) {
return 0;
}
int wordCount = 0;
bool isWord = false;
int endOfLine = n - 1;
for (int i = 0; i < n; i++) {
// Check if the character is a letter
// and index of character array doesn't
// equal to end of line that means, it is
// a word and set isWord by true
if (isalpha(str[i]) && i != endOfLine) {
isWord = true;
}
// Check if the character is not a letter
// that means there is a space, then we
// increment the wordCount by one and set
// the isWord by false
else if (!isalpha(str[i]) && isWord)
{
wordCount++;
isWord = false;
}
// Check for the last word of the
// sentence and increment the wordCount
// by one
else if (isalpha(str[i]) && i == endOfLine) {
wordCount++;
}
}
// Return the total number of
// words in the string
return wordCount;
}
// Driver code
int main()
{
char str[] = "One two three\n four\tfive ";
int n = (sizeof(str) / sizeof(char)) - 1;
cout << "No of words : " << countWords(str, n);
return 0;
}
// This is code is contributed by Aarti_Rathi
Java
// Java program to count total
// number of words in the string
class GFG
{
// Function to count total number
// of words in the string
public static int
countWords(String str)
{
// Check if the string is null
// or empty then return zero
if(str == null || str.isEmpty())
return 0;
int wordCount = 0;
boolean isWord = false;
int endOfLine = str.length() - 1;
// Converting the given string
// into a character array
char[] ch = str.toCharArray();
for (int i = 0; i < ch.length; i++) {
// Check if the character is a letter
// and index of character array doesn't
// equal to end of line that means, it is
// a word and set isWord by true
if (Character.isLetter(ch[i])
&& i != endOfLine)
isWord = true;
// Check if the character is not a letter
// that means there is a space, then we
// increment the wordCount by one and set
// the isWord by false
else if (!Character.isLetter(ch[i])
&& isWord) {
wordCount++;
isWord = false;
}
// Check for the last word of the
// sentence and increment the wordCount
// by one
else if (Character.isLetter(ch[i])
&& i == endOfLine)
wordCount++;
}
// Return the total number of
// words in the string
return wordCount;
}
// Driver Code
public static void main(String args[])
{
// Given String str
String str =
"One two three\n four\tfive ";
// Print the result
System.out.println("No of words : " +
countWords(str));
}
}
// This code is contributed by Prashant Srivastava
Python3
# Python program to count total
# number of words in the string
# Function to count total number
# of words in the string
def countWords(Str):
# Check if the string is null
# or empty then return zero
if(Str == None or len(Str) == 0):
return 0
wordCount = 0
isWord = False
endOfLine = len(Str) - 1
# Converting the given string
# into a character array
ch = list(Str)
for i in range(len(ch)):
# Check if the character is a letter
# and index of character array doesn't
# equal to end of line that means, it is
# a word and set isWord by true
if(ch[i].isalpha() and i != endOfLine):
isWord = True
# Check if the character is not a letter
# that means there is a space, then we
# increment the wordCount by one and set
# the isWord by false
elif(not ch[i].isalpha() and isWord):
wordCount += 1
isWord = False
# Check for the last word of the
# sentence and increment the wordCount
# by one
elif(ch[i].isalpha() and i == endOfLine):
wordCount += 1
# Return the total number of
# words in the string
return wordCount
# Driver Code
# Given String str
Str = "One two three\n four\tfive "
# Print the result
print("No of words :", countWords(Str))
# This code is contributed by rag2127
C#
// C# program to count total
// number of words in the string
using System;
public class GFG
{
// Function to count total number
// of words in the string
static int countWords(String str)
{
// Check if the string is null
// or empty then return zero
if(str == null)
{
return 0;
}
int wordCount = 0;
bool isWord = false;
int endOfLine = str.Length - 1;
// Converting the given string
// into a character array
char[] ch = str.ToCharArray();
for (int i = 0; i < ch.Length; i++)
{
// Check if the character is a letter
// and index of character array doesn't
// equal to end of line that means, it is
// a word and set isWord by true
if (Char.IsLetter(ch[i])
&& i != endOfLine)
{
isWord = true;
}
// Check if the character is not a letter
// that means there is a space, then we
// increment the wordCount by one and set
// the isWord by false
else if (!Char.IsLetter(ch[i])
&& isWord)
{
wordCount++;
isWord = false;
}
// Check for the last word of the
// sentence and increment the wordCount
// by one
else if (Char.IsLetter(ch[i])
&& i == endOfLine)
{
wordCount++;
}
}
// Return the total number of
// words in the string
return wordCount;
}
// Driver Code
static public void Main ()
{
// Given String str
string str = "One two three\n four\tfive ";
// Print the result
Console.WriteLine("No of words : " + countWords(str));
}
}
// This code is contributed by avanitrachhadiya2155
Javascript
<script>
// Javascript program to count total
// number of words in the string
// Function to count total number
// of words in the string
function countWords(str)
{
// Check if the string is null
// or empty then return zero
if(str == null || str.length==0)
return 0;
let wordCount = 0;
let isWord = false;
let endOfLine = str.length - 1;
// Converting the given string
// into a character array
let ch = str.split("");
for (let i = 0; i < ch.length; i++) {
// Check if the character is a letter
// and index of character array doesn't
// equal to end of line that means, it is
// a word and set isWord by true
if (isLetter(ch[i])
&& i != endOfLine)
isWord = true;
// Check if the character is not a letter
// that means there is a space, then we
// increment the wordCount by one and set
// the isWord by false
else if (!isLetter(ch[i])
&& isWord) {
wordCount++;
isWord = false;
}
// Check for the last word of the
// sentence and increment the wordCount
// by one
else if (isLetter(ch[i])
&& i == endOfLine)
wordCount++;
}
// Return the total number of
// words in the string
return wordCount;
}
function isLetter(c) {
return c.toLowerCase() != c.toUpperCase();
}
// Driver Code
// Given String str
let str="One two three\n four\tfive ";
// Print the result
document.write("No of words : " +
countWords(str));
// This code is contributed by ab2127
</script>
Publicación traducida automáticamente
Artículo escrito por GeeksforGeeks-1 y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA