One of the main reasons of Roman Empire's fall is that they could not terminate their C programs :o)

RECURSION & EXHAUSTIVE SEARCH (programmed in 1994)
MINES.C This C program tries to find the mines located on a map. The rule of the input map is that : map contains positive numbers which are equal to the number of mines around that number's position including the position of the number. (Just like minesweeper)
Example : Input given to the program Original mine locations
3 4 2 1 2 2
3 5 3 2 3 3
2 4 3 3 3 3
1 3 3 4 3 3
2 4 4 4 2 2
2 4 4 3 1 1
x . . . . x
x x x . . x
. . x . . x
. . . . x .
. x x . x .
. x x . . .
NOTE : This program can be very handy to start with if you want to get into recursion and exhaustive search.