diff --git a/README.md b/README.md
index 9138d3aafca91ed1b15ca141ff43cdbec1000995..3df0adca5385c635bd50b310b1b6ecebffeefbd1 100644
--- a/README.md
+++ b/README.md
@@ -4,3 +4,8 @@
 
 실전코딩2 실습
 
+## printf
+
+### stdio.h
+
+redirection stderr, stdout, stdin에 대해서 배웠음
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