c++ - How to allow user to do input more than twice? -

i new c++. trying understand how utilize c++ common input (cin). trying write program checks amount of characters of sentence , amount of vowels in input sentence. have done it, problem happens when try code run through 1 more time. when runs through 1 more time, doesn't allow second input anymore. simplified code below.

#include <iostream> #include <string>  using namespace std;  int main() {   char rerun = 'y';   string input;   int a_counter, e_counter, i_counter, o_counter, u_counter;   a_counter = e_counter = i_counter = o_counter = u_counter = 0;      {     getline(cin, input); // asking user input sentence     // written code here uses loop vowel counting     // written code use cout command output result     cin >> rerun; // ask type 'y' or 'n' continue, assume user types y or n   } while (rerun == 'y'); } //end of main function 

when running program, @ first user allowed input sentence and, after input , result displayed, user asked put in 'y' or 'n'. if answer y, code not allow put in sentence (where getline is) , display result of (a_counter...) 0 , jump straight requesting put 'y' or 'n'. can me? appreciated.

when line

cin >> rerun; 

is executed, '\n' left in input stream. next time run

getline(cin, input); 

you empty line.

to fix problem, add line

cin.ignore(); 

right after

cin >> rerun; 

here's loop should like:

do {   getline(cin, input);   cin >> rerun;   cin.ignore(); }while (rerun == 'y');