DWITE Online Computer Programming Contest
February 2009
Problem 1
Baby Diff

While diff is a useful text processing utility that finds the differences between contents of files, this baby diff will start out as a simplistic check, counting how many of the leading characters of two lines of text are the same. The hopes and dreams of this program is to grow up into a full-fledged utility, but for now, it starts small.

The input file DATA1.txt will contain 5 sets of input, two lines each. Each line will be a non-empty string, less than 255 characters long.

The output file OUT1.txt will contain 5 lines of output, integers 0 <= i <= 255 -- number of leading characters that are the same between the two lines, up to the first difference.

Note: that the two lines could be of different length. The counter stops before the first character that doesn't match, so two strings that start differently would have a result of 0. Make sure not to count the linebreak characters such as \n, \r, or a combination there of.

Sample Input:
tony
tony
dan
tony
one two three
one two four
a
b
abcd
abcde
		        
Sample Output:
4
0
8
0
4