How to count number of occurrences of pattern within a string?

Count number of occurrences of characters in a string C++?

• I am having problems with a program I am writing in C++. It is suppose to take a user created sentence then out put the number of occurrences for the letters that make up the string. ...show more

• Answer:

  This is a solution not using map, but an array of integers. It also shows you how remove_if works for you: #include <iostream> #include <algorithm> using namespace std; int main() { int ar[127] = {0}; string userInput; cout << "\nYour input> "; getline(cin, userInput); string::iterator pend = remove_if(userInput.begin(), userInput.end(), [](const char& c){return c==' ' ? true : false;}); userInput.resize( distance( userInput.begin(), pend ) ); for(int i=0; i<userInput.length( ); i++) ar[userInput[i]]++; cout << "Your line of text contains the following characters:" << endl; for(int i = 0; i < 127; i++) { if (ar[i]) cout << (char)i << " " << ar[i] << endl; } return 0; }