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Tutorials - Bitwise Operators and Bit Manipulations in C and C++ - Cprogramming.com

[edit] Sorry, iMalc, didn't mean to trample on your post.

if( input == NULL )
//if there is no such file
{
printf("Cannot open file [%s] \n", "input");
flag = 1;
}

if( fscanf(input, "%d", &N) != 1 )
//if the first thing is not a number
{