How to test if a file has valid input

[DolphinLover55]

I have written a program which opens a file of integers and computes max, min, average, total. I need to implement code which tests if there is any valid data in the file (i.e., if there are any lines in the file). I know I should use an if statement, but what condition would I put?

Thanks

[JLBorges]

#include <iostream>
#include <fstream>

int main()
{
    // if( std::ifstream file{ "numbers.txt" } ) // canonical
    std::ifstream file( "numbers.txt" ) ;

    int cnt = 0 ;

    int number ;
    while( file >> number ) // for each number in the file
    {
        ++cnt ; // increment count
        // add to total
        // check for min, max
    }

    if( cnt > 0 ) // if at least one number was read
    {
        // caculate average
        // print results
    }
    else
    {
        std::cerr << "error in reading numbers from file\n" ;
    }
}