/* Input : The word to search for space or enter, then the string/line in which to search and submit The program counts overlapping words also. */ #include #include int main() { std::string word, line; std::cin >> word; getline(std::cin ,line); size_t pos=0, cnt=0; while(std::string::npos != (pos = line.find(word, pos))){++cnt; pos+=1;}; std::cout << "num times word " << word << " appears in" << line << " = " << cnt; } /* Explanation on Anmol's request. Here is how the program works : 1. Get the string to search into string object word 2. Get the sentence from user in which to search for the word. Notice the word to search is read in string object directly where as sentence to search in is read using getline function. This is because getline doesn't skip whitespace where as string object will not read (using cin) further if it encounter whitespace. 3. Once you have input, use the string find function to search the string read in step 1. find function can scan for single character or multi-character strings. 4. If a string is found then the find function returns the starting position of the string. So increament the counter. 5. If the string is not found then find function returns a value string::npos. This is very large value way more than the length of the string. 6. Once you have found the string, you need to scan the remaining sentence to find if there are more occurances of the word, so to accomplish you start scanning the string from the pos(returned in step 4) + 1 till the end of the string and repeat the steps till the whole sentence is scanned. Note : I started with pos+1 for the next string(word) search because i want to find the overlapping strings to i.e in an input like aaa and string to scan is aa then there are two occurances of aa in input. If the overlapping strings are not desired then you need to scan for next string from pos + length of the string to search for. 7. At the end of the process you have the number of time a search word appears in the string(sentence) or 0 if the word to search is not found in the sentence. Note the position returned is 0 index based i.e it starts from 0 not 1 */

word_frequency_in string.cpp