print 2nd word in a string with its size in C++

Question

I am trying to make a program in which a user enters a string and i will print out the second word in the string with its size. The delimiter's are space( ), comma(,) and tab( ). I have used a character array and fgets to read from user and a character pointer that points to the first element of the array.

source code:

#include"iostream"
#include<stdio.h>
#include<string>

using namespace std;

// extract the 2nd word from a string and print it with its size(the number of characters in 2nd word)

int main()
{
    char arr[30], arr1[30];
    char *str = &arr1[0];

    cout<<"Enter a string: ";
    fgets(str, 30, stdin);

    int i = 0, j, count = 1, p = 0;     // count is used to find the second word
    // j points to the next index where the first delimiter is found.
    // p is used to store the second word found in character array 'arr'

    while(*(str+i) != '\n')
    {
        if(*(str+i) == ' ' || *(str+i) == ',' || *(str+i) == '  ')
        {
            count++;

            if(count == 2)
            {
                // stroing 2nd word in arr character array
                j = i+1;    
                while(*(str+j) != ' ' || *(str+j) != ',' || *(str+j) != '   ')
                {
                    arr[p] = *(str+j);
                    cout<<arr[p];
                    p++;
                    i++;
                    j++;
                }
                break;
            }

        }
        i++;
    }

    arr[p+1] = '\0';        // insert NULL at end

    i = 0;
    while(arr[i] != '\0')
    {
        cout<<arr[i];
        i++;
    }

    cout<<"("<<i<<")"<<endl;

    return 0;
}

Help me out with this.

Answer 1

To start, don't use std::cin for testing. Just set a value in your code for consistency and ease of development. Use this page for a reference.

#include <iostream>
#include <string>

int main() {
    std::string str("this and_that are the tests");
    auto start = str.find_first_of(" ,\n", 0);
    auto end = str.find_first_of(" ,\n", start + 1);
    std::cout << str.substr(start, end - start);
    return 0;
}

And this is still somewhat of a hack, it just depends where you are going. For instance the Boost library is rich with extended string manipulation. If you are going to parse out more than just one word it can still be done with string manipulations, but ad-hoc parsers can get out of hand. There are other tools like Boost Spirit to keep code under control.

Answer 2

The delimiters used when extracting from a stream depends on the locale currently in effect. One (cumbersome) way to change the extraction behaviour is to create a new locale with a special facet in which you specify your own delimiters. In the below example the new locale is used to imbue a std::stringstream instead of std::cin directly. The facet creation part is mostly copy/paste from other answers here on SO, so you'll find plenty of other examples.

#include <iostream>
#include <locale>    // std::locale, std::ctype<char>
// https://en.cppreference.com/w/cpp/locale/ctype_char
#include <sstream>   // std::stringstream
#include <algorithm> // std::copy_n
#include <vector>    // a container to store stuff in

// facet to create our own delimiters
class my_facet : public std::ctype<char> {
    mask my_table[table_size];
public:
    my_facet(size_t refs = 0)
        : std::ctype<char>(&my_table[0], false, refs)
    {
        // copy the "C" locales table to my_table
        std::copy_n(classic_table(), table_size, my_table);
        // and create our delimiter specification
        my_table[' '] = (mask)space;
        my_table['\t'] = (mask)space;
        my_table[','] = (mask)space;
    }
};

int main() {
    std::stringstream ss;
    // create a locale with our special facet
    std::locale loc(std::locale(), new my_facet);
    // imbue the new locale on the stringstream
    ss.imbue(loc);

    while(true) {
        std::string line;
        std::cout << "Enter sentence: ";
        if(std::getline(std::cin, line)) {
            ss.clear(); // clear the string stream from prior errors etc.
            ss.str(line); // assign the line to the string stream

            std::vector<std::string> words; // std::string container to store all words in
            std::string word; // for extracting one word

            while(ss>>word) { // extract one word at a time using the special facet
                std::cout << "  \"" << word << "\" is " << word.size() << " chars\n";
                // put the word in our container
                words.emplace_back(std::move(word));
            }
            if(words.size()>=2) {
                std::cout << "The second word, \"" << words[1] << "\", is " << words[1].size() << " chars\n";
            } else {
                std::cout << "did not get 2 words or more...\n";
            }
        } else break;
    }
}

Answer 3

#include"iostream"
#include<stdio.h>
#include<string>
#include <ctype.h>

using namespace std;


int main()
{
    char c;
    string str;
    char emp = ' ';
    cout<<"Enter a string: ";
    getline (cin,str);


    int  j = 0, count = 1, counter = 0;  


    for (int i = 0; i < str.length() && count != 2; i++)
    {
        cout<< str[i] <<endl;
        if( isspace(str[i]) || str[i] == ',' || str[i] == '\t' )
        {
            count++;

            if(count == 2)
            {
                j = i+1;
                while(j < str.length())
                {
                    if (isspace(str[j]) || str[j] == ',' || str[j] == '\t')
                    {
                        break;

                    }
                    cout<<str[j];
                    counter++;
                    j++;
                }
                cout<<endl;
            }

        }
    }



    cout<<"size of the word: "<<counter<<endl;

    return 0;


}

This is a simple answer to what you want, hope to help you.

Answer 4

// Paul Adrian P. Delos Santos - BS Electronics Engineering
// Exercise on Strings

#include <iostream>
#include <sstream>

using namespace std;

int main(){
    
    // Opening Message
    
    cout << "This program will display the second word and its length.\n\n";
    
    // Ask for a string to the user.
        
    string input;   
    cout << "Now, please enter a phrase or sentence: ";
    getline(cin, input);
    
    // Count the number of words to be used in making a string array.
    
    int count = 0;
    int i;
    
    for (i=0; input[i] != '\0'; i++){
        if (input[i] == ' ')
            count++;        
    }
    
    int finalCount = count + 1;
    
    // Store each word in a string array.
    
    string arr[finalCount];
   
    int j = 0;
    stringstream ssin(input);
   
    while (ssin.good() && j < finalCount){
        ssin >> arr[j];
        j++;
    }
    
    // Display the second word and its length. 
    
    string secondWord = arr[1];
    
    cout << "\nResult: " << arr[1] << " (" << secondWord.size() << ")";
    
    return 0;
}