char menu();int vowel_counter(const std::string&);int consonants_counter(const std::string&); void cls( HANDLE );int main(){   std::string input;   cout<<"Enter a string ";   std::getline(std::cin, input);   char menu_input = menu();   while(toupper(menu_input) != 'E')   { 		if(toupper(menu_input) == 'A') 		  {				cout<<"The number of vowels in your string is "<<vowel_counter(input)<<endl;				cout<<"Press a key to continue"<<endl;					cin.ignore();					cin.get(); 		  } 		else if(toupper(menu_input) == 'B') 				{	 				cout<<"the number of consonants in your string is "<<consonants_counter(input)<<endl;					cout<<"Press a key to continue"<<endl;					cin.ignore();					cin.get(); 				}		else if(toupper(menu_input) == 'C')				{				  cout<<"The count of both consonants and vowels is "<<vowel_counter(input) +  consonants_counter(input)<<endl;				  cout<<"Press a key to continue"<<endl;				  cin.ignore();					cin.get();		        }		else if(toupper(menu_input) == 'D')		    {			    cout<<"Enter a string ";				cin.ignore(); 				cin.getline(input, SIZE);		    }          menu_input = menu(); }cout<<"Exiting the program "<<endl;system("PAUSE");return 1;}char menu(){	 HANDLE  hConsole;   hConsole = GetStdHandle(STD_OUTPUT_HANDLE);cls(hConsole);char input;    cout<<"\t\tCount Vowels, Consonants or Both."<<endl<<endl;	cout<<"\t A) Count the number of vowels in the string"<<endl		<<"\t B) Count the number of consonants in the string"<<endl		<<"\t C) Count both the vowels and consonants int the string"<<endl		<<"\t D) Enter another string"<<endl		<<"\t E) Exit the program"<<endl<<endl		<<"\t Enter a letter ";	cin>>input;return input;}int vowel_counter(const std::string& str){	char vowles[5]={'A', 'E','I', 'O', 'U'};	int counter = 0;	for(size_t i=0; i<str.length() ++i)	{		for(int j=0; j<5; ++j)		{			if(toupper(str) == vowles[j])			{				counter++;			}		}	}return counter;}int consonants_counter(const std::string& str){char consonants[21]={'B', 'C','D', 'F', 'G', 'H' ,'J','K','L','M','N','P','Q','R','S','T','V','W','X','Y','Z'};	int counter = 0;	for(size_t i=0; i<str.length() ++i)	{		for(int j=0; j<5; ++j)		{			if(toupper(str) == consonants[j])			{				counter++;			}		}	}return counter;}

To append string 'x' to string 'y', given 'len' is the length of 'y':  Increase 'len' by the length of 'x' - 1.  (The -1 is because there is a null terminator in the buffer that we won't be appending)  Allocate len-many bytes into 'temp'.  Copy string data from 'y' to 'temp'.  Append string data from 'x' to 'temp' (starting by over-writing the null terminator from the 'input' data).  Deallocate 'y'.  Point 'y' at 'temp'.'input' points to a new array of 1 character, with the value '\0'.(That allows uniform handling inside the loop).'buffer' is an empty array of chars.'len' is a counter for the length of the data 'input' points at.Repeat:  Read from cin into 'buffer', up to the size of 'buffer'.  If the fail bit is set on cin:    Append 'buffer' to 'input' by the above process.    Reset the fail bit on cin.  Otherwise:    Exit the loop.Append 'buffer' to 'input' by the above process. (To handle any "left-over" part).