buffered vs normal i/o

i see many solutions in codechef in c c++ using buffered i/o and other complex i/o methods. a simple 5 line code becomes a complex looking code of 2 page using buffers etc. but the running time is considerably affected. my simple code in which i use scanf printf cin cout takes 2-5 seconds for running while these buffered i/o solutions run in about 0.13 seconds. how is that ??? please post a tutorial so that we can read it and understand it and may be use it in future …

i have referred to c and c++ …
plz answer

Do not ask question multiple times! (http://discuss.codechef.com/questions/986/buffered-io-vs-standard-io)

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