Visual Studio Gives Ambiguous Error for No Real Reason - c++

Question

It gives the following error:
error C2872: 'count' : ambiguous symbol
Count variable has been declared as a global variable and the code compiles and runs in Sublime Text. Don't understand why Visual Studio is crying over it.
#include <iostream>
#include <fstream>
using namespace std;
int** am; // Adjacency matrix
int* ar, * ar2; // Arrays to work with
int n; // Number of nodes
int node1, node2, k; // For reading input from the console
int count;
bool checkReachability(int, int, int);
void fillArray(int);
void updateArray(int,int);
void freeMemory();
int main() {
ifstream in;
in.open("Input2.txt");
int a, b;
if(in.is_open()) {
in >> n;
// Allocate memory on the heap dynamically for the adjacency matrix:
am = new int*[n];
ar = new int[n];
ar2 = new int[n];
for (int i = 0; i < n; i++) {
am[i] = new int[n];
}
// Initialize the values of the adjacency matrix with 0s and the principle diagonal with 1s initially:
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
if (i == j) {
am[i][j] = 1;
} else {
am[i][j] = 0;
}
}
}
while(!in.eof()) {
in >> a >> b;
am[a-1][b-1] = 1;
}
cout << "The adjacency matrix input is as follows: \n\n";
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
cout << am[i][j] << " ";
}
cout << endl << endl;
}
in.close();
} else {
cout << "\nError reading the input file\n\n";
}
char c;
do {
cout << "\nPlease enter the input (node1, node2, k): \n";
cin >> node1 >> node2 >> k;
fillArray(node1-1);
count = 0;
if(checkReachability(node1-1,node2-1,k)) {
cout << "\nReachable within " << k << " steps";
if (count < k) {
cout << " (actually " << count << ")";
}
cout << endl << endl;
} else {
cout << "\nNot reachable within " << k << " steps \n";
}
cout << "\nDo you want to continue? Y/N \n\n";
cin >> c;
} while (c == 'Y' || c == 'y');
freeMemory();
system("pause");
return 0;
}
bool checkReachability(int n1, int n2, int k) {
if (n1 == n2) return true;
count++;
if (count <= k) {
if (ar[n2] != 0) return true;
int x;
for (int i = 0; i < n; i++) {
if (ar[i] != 0 && i != n1) {
ar[i]++;
x = ar[i];
}
}
for(int i = 0; i < n; i++) {
ar2[i] = ar[i];
}
for(int i = 0; i < n; i++) {
if (ar2[i] == x) {
fillArray(i);
updateArray(x,i);
if (checkReachability(ar2[i], n2, k)) return true;
}
}
}
return false;
}
void fillArray(int x) {
// To fill the array with the adjacencies of a particular node
for(int i = 0; i < n; i++) {
ar[i] = am[x][i];
}
}
void updateArray(int x, int y) {
for(int i = 0; i < n; i++) {
if (ar[i] == 1 && i != y) {
ar[i] = x;
}
}
}
void freeMemory() {
// To free the dynamically allocated memory on the heap
for (int i = 0; i < n; i++) {
delete [] am[i];
}
delete [] ar;
delete [] ar2;
}

Answer 1

using namespace std is your problem.
Looks like the Microsoft implementation of either the iostream or fstream headers themselves include algorithm. This is causing the name clash with std::count().

Answer 2

So, as #Retiredninja suggested, if I choose to replace while(!in.eof()) with while(in >> a >> b) in:
while(!in.eof()) {
in >> a >> b;
am[a-1][b-1] = 1;
}
Does the rest of the code in the while loop remain the same or does it mean, the input has already been read into a and b when the condition is checked in while(in >> a >> b)?
And become the following:
while(in >> a >> b) {
am[a-1][b-1] = 1;
}
or does it remain:
while(in >> a >> b) {
in >> a >> b;
am[a-1][b-1] = 1;
}