Converting call from a .txt into a string c++ - c++

Question

I'm trying to read from a text file and then count the number of occurences of each word and then export the results to a different text file. I'm only allowed to use loops and arrays for this assignment. I'm just looking for a slight push in the right direction, primarily in the beginning of the code. It's not compiling correctly!
using namespace std;
#include <iostream>
#include <iomanip>
#include <string>
#include <fstream>
void put(string word, string words[], int counts[], int & size)
{
int w;
for (w = 0; w < size && word >= words[w]; w++);
if (w >= size) {
words[w] = word;
counts[w] = 1;
++size;
}
else if (word < words[w]) {
for (int i = size - 1; i >= w; i--) {
words[i + 1] = words[i];
counts[i + 1] = counts[i];
}
words[w] = word;
counts[w] = 1;
++size;
}
else {
counts[w] = counts[w] + 1;
}
}
int main()
{
int word;
ifstream input("input.txt");
ofstream chout("charcount.txt");
ofstream wout("wordscounts.txt");
int inputSize = sizeof(input) / sizeof(string);
int counts[100];
const int MAX = 100;
string words[MAX];
int wordsSize = 0;
while (input >> word) {
put(input[word], words, counts, wordsSize);
}
wout << " Word Frequency" << endl;
for (word = 0; word < inputSize; ++word) {
wout << setw(10) << words[word] << setw(4) << counts[word] << endl;
}
chout.close();
wout.close();
system("pause");
return 0;
}

Answer 1

This line:
put(input[word], words, counts, wordsSize);
You are trying to index into an ifstream. This is simply not allowed. The compiler (g++ 4.8.4) said:
no match for ‘operator[]’ (operand types are ‘std::ifstream {aka std::basic_ifstream<char>}’ and ‘int’)