diff --git a/cv1/program.c b/cv1/program.c
new file mode 100644
index 0000000..5a83bef
--- /dev/null
+++ b/cv1/program.c
@@ -0,0 +1,11 @@
+#include <"stdio.h">
+
+char simulate_caps_lock(char c) {
+    if ('a' <= c && c <= 'z') {
+        return c - ('a' - 'A');
+    } else if ('A' <= c && c <= 'Z') {
+        return c + ('a' - 'A');
+    } else {
+        return c;
+    }
+}