How to count am,is,are (to be) from a text file?

[Unicepter]

Hey guys, I need a program which counting am,is,are from a text file.
I find lots of program which is counting vowels from in a text file
But when i use am to any vowel place it gives me to this error.

[Warning] multi-character character constant [-Wmultichar]

This is the codes when i trying to change. Please help me..

  #include <iostream>
#include<fstream>
using namespace std;

int main(  )
{
	fstream file; 
	char c;
	int nNum = 0, x=0, y=0, z=0;

	file.open("words.txt");
	while(!file.eof())
	{
		file.get(c);
		if (c == 'a' || c == 'e' ||  c == 'o' ||  c == 'i' || c == 'u')
			nNum++;
		if (c == 'a')
			x++;
		if (c == 'e')
			y++;
		if (c == 'o')
			z++;
	}
	file.close();
	cout << nNum <<endl;
	cout<<"Number of a :"<<x<<endl;
	cout<<"Number of e :"<<y<<endl;
	cout<<"Number of o :"<<z<<endl;
	return 0;
}

[48T7M4Gy]

use strings instead of single char's as in line 8

[cire]

Something like this?

#include <fstream>
#include <iostream>
#include <string>
#include <unordered_map>

int main()
{
    using dictionary = std::unordered_map<std::string, unsigned>;
    dictionary words_to_track = 
    { 
        {"am", 0}, {"be", 0}, {"are", 0},
        {"was", 0}, {"were", 0}, {"been", 0}
    };

    std::ifstream in("words.txt");

    std::string token;
    while (in >> token)
    {
        if (words_to_track.count(token))
            ++words_to_track[token];
    }

    for (auto& pair : words_to_track)
        std::cout << pair.first << ": " << pair.second << '\n';
}

Untested. Doesn't make any attempt to handle variations in case or contractions.