diff --git a/code_study/Baekjoon/c/11723.c b/code_study/Baekjoon/c/11723.c
new file mode 100644
index 0000000..df5eafd
--- /dev/null
+++ b/code_study/Baekjoon/c/11723.c
@@ -0,0 +1,34 @@
+#define _CRT_SECURE_NO_WARNINGS
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+int main() {
+    int set = 0;
+    int N;
+    scanf("%d",&N);
+    getchar();
+    while(N--) {
+        char str[20];
+        if (fgets(str, sizeof(str), stdin) == NULL) break;
+        if (str[0] == '\n') { N++; continue; }
+        str[strcspn(str, "\n")] = 0;
+        char *opcode = strtok(str, " ");
+        char *operend = strtok(NULL, " ");
+        
+        if(!strcmp(opcode, "add")) {
+            set |= 1 << (atoi(operend)-1);
+        } else if(!strcmp(opcode, "remove")) {
+            set &= ~(1 << (atoi(operend)-1));
+        } else if(!strcmp(opcode, "check")) {
+            printf("%d\n",set & (1 << (atoi(operend)-1)) ? 1 : 0);
+        } else if(!strcmp(opcode, "toggle")) {
+            set ^= 1 << (atoi(operend)-1);
+        } else if(!strcmp(opcode, "all")) {
+            set = (1<<20) - 1;
+        } else if(!strcmp(opcode, "empty")) {
+            set = 0;
+        }
+    }
+    return 0;
+}