diff --git a/c_primer_plus/chapter03/Makefile b/c_primer_plus/chapter03/Makefile
index a3e7363..fde7262 100644
--- a/c_primer_plus/chapter03/Makefile
+++ b/c_primer_plus/chapter03/Makefile
@@ -1,9 +1,8 @@
 SRC := $(shell ls *.c)
 
 
-
 %: %.c
-	gcc -Wall -Wextra $@.c -o $@
+	gcc -std=c11 -Wall -Wextra $@.c -o $@
 
 
 .PHONY: clean
diff --git a/c_primer_plus/chapter04/Makefile b/c_primer_plus/chapter04/Makefile
index 80acd02..fde7262 100644
--- a/c_primer_plus/chapter04/Makefile
+++ b/c_primer_plus/chapter04/Makefile
@@ -2,7 +2,7 @@ SRC := $(shell ls *.c)
 
 
 %: %.c
-	gcc -Wall -Wextra $@.c -o $@
+	gcc -std=c11 -Wall -Wextra $@.c -o $@
 
 
 .PHONY: clean
diff --git a/c_primer_plus/chapter05/Makefile b/c_primer_plus/chapter05/Makefile
index 4ccd9a2..9dea1cf 100644
--- a/c_primer_plus/chapter05/Makefile
+++ b/c_primer_plus/chapter05/Makefile
@@ -2,7 +2,7 @@ SRC := $(shell ls *.c)
 
 
 %: %.c
-	gcc -Wall -Wextra $@.c -o $@
+	gcc -std=c11 -Wall -Wextra $@.c -o $@
 
 
 .PHONY: clean
diff --git a/c_primer_plus/chapter06/Makefile b/c_primer_plus/chapter06/Makefile
index 4ccd9a2..9dea1cf 100644
--- a/c_primer_plus/chapter06/Makefile
+++ b/c_primer_plus/chapter06/Makefile
@@ -2,7 +2,7 @@ SRC := $(shell ls *.c)
 
 
 %: %.c
-	gcc -Wall -Wextra $@.c -o $@
+	gcc -std=c11 -Wall -Wextra $@.c -o $@
 
 
 .PHONY: clean