Text versus Binary Mode: End of File
The second difference between text and binary modes is in the way the end-of-file is detected. In text mode, a special character, whose ASCII value is 26, is inserted after the last character in the file to mark the end of file. If this character is detected at any point in the file, the read function would return the EOF signal to the program.
As against this, there is no such special character present in the binary mode files to mark the end of file. The binary mode files keep track of the end of file from the number of characters present in the directory entry of the file.
There is a moral to be derived from the end of file marker of text mode files. If a file stores numbers in binary mode, it is important that binary mode only be used for reading the numbers back, since one of the numbers we store might well be the number 26 (hexadecimal 1A). If this number is detected while we are reading the file by opening it in text mode, reading would be terminated prematurely at that point.
Thus the two modes are not compatible. See to it that the file that has been written in text mode is read back only in text mode. Similarly, the file that has been written in binary mode must be read back only in binary mode.
As against this, there is no such special character present in the binary mode files to mark the end of file. The binary mode files keep track of the end of file from the number of characters present in the directory entry of the file.
There is a moral to be derived from the end of file marker of text mode files. If a file stores numbers in binary mode, it is important that binary mode only be used for reading the numbers back, since one of the numbers we store might well be the number 26 (hexadecimal 1A). If this number is detected while we are reading the file by opening it in text mode, reading would be terminated prematurely at that point.
Thus the two modes are not compatible. See to it that the file that has been written in text mode is read back only in text mode. Similarly, the file that has been written in binary mode must be read back only in binary mode.
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