I have an inquiry about reading from a file. so if i have a file and if it opens (meaning it is there) how do i check if there is data?

ifstream file("example.txt");
    if (file.good())                        
        //file.open("example.txt"); // is this necessary again???????? i read that the ".good" provide checking if file exists AND opens it if it does

        //check if there is data...how????

i know if i have like getline and if it cant get anything, the program will obviously crash/not build, but instead of crashing, i want to make it a message that there is no data in file.

thanks in advance

3 Years
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Last Post by catastrophe2

f i have like getline and if it cant get anything, the program will obviously crash/not build

No. std::getline() first clears the string and if no characters were extracted (not even the discarded delimiter), sets the failbit on the stream.

if( std::getline( stm, line ) ) \\ if at least one character was extracted

#include <iostream>
#include <fstream>

int main()
    const char* const path_to_file = __FILE__ ; // put the actual path here 
    std::ifstream file(path_to_file) ;

    if( !file.is_open() ) std::cerr << "could not open file\n" ;
    else if( file.peek() == EOF ) std::cout << "file is empty\n" ;
    else std::cout << "file contains at least one character\n" ;

thanks, i implemented it in mine, however im getting an exception error because i have a statement to print the data from the file after it opens successfully. however, in the case of being empty, i want it to say press any key to continue (as in exit the program) and not put for say "the line from the file is: (nothing because in the case of empty it cout's nothing which is good, but i dont want it to say this anyways...
so basically its gonna say open sucessful, file is empty, press any key to continue, (of which it exits when user presses key)

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