What is the best way to count the number of words in a sentence?

#include<iostream> #include <string> using namespace std; int main() { string content; int index; int wordcount = 1; getline(cin, content); for( index = 1; index < content.length(); index++ ) { if( content[i] == ' ' && content[i - 1] != ' ' ) { wordcount++; } } cout << wordcount; return 0; }

This can be made as arbitrarily complex as you'd like due to the "in a sentence" portion of your question.  Parsing out what defines inter-sentence-gaps can be a bear - trust me. However, once you had a string/stream that contains the sentence content only, the basic algorithm's super simple - all you really need to do is to count the gaps between words, and add one, or use a languages capability to split a string into words, using spaces/tabs/cr/lf/whatever as separators, and ask how large the resulting collection of sub-strings is. posted a comment on Sagar's C++ answer showing how this can be done with one line of Python code.  It can similarly be done with just a little perl, or awk even.

#include <iostream> #include <sstream> using namespace std; int main() { string line, word; getline(cin, line); stringstream ss(line); int word_count = 0; while(getline(ss, word, ' ')) word_count += word.length() ? 1 : 0; cout << word_count; return 0; } Edit : Thanks to Vivek Nagarajan for pointing out this possible flaw. Using bool directly in arithmetic may not always be a good idea as some compilers might not have 'true' set to 1.