使用正则表达式检查.dat文件

I am reading a file using fgets. I need to check each line of the file against a regex. If there is a non alpha numeric character, it needs to exit the program with the line number and "bad" character displayed. What is happening is it is kicking out before the "bad" character. Here is my .dat file:I am reading a file using fgets. I need to chec