regarding file existence check within a for loop in C++

I 开发者_如何学Goam attempting to check if a file exists, and then if so proceed with a task and if not to just output that there is no such file. I have done this in other code but it doesn't seem to be working with my current code.

The basics of it read:

count=argc;


for(i=0; i < count-1; i++)
{
    filename[i] = argv[i+1];
}


for( i=0; i < count-1; i++)
      {
      int tempi=i;
      ifstream infile(filename[i].c_str());

           if(infile)
           {
           //do things
           }
           else
           {
           cout<<"no file"<<endl;
           }

You need to call infile.is_open(). Also, do you plan to do something with the file if it exists, or not?

The canonical way to access argv is:

int main( int argc, char * argv[] ) {
    for ( int i = 1; i < argc; i++ ) {
        // do something with argv[i]
    }
}

infile, in the conditional, evaluates to false when the stream is in a "bad" state.

However, merely failing to open a file does not leave the stream in a bad state (welcome to C++!). Only after attempting to read from the stream would this mechanism work for you.

Fortunately, you can use infile.is_open() to explicitly test for whether the stream was opened or not.

Edit

The above is not true.

Testing the stream state is sufficient, and I can't see anything wrong with your code.