From 1fdf60275452094b6ae9fb3e5696e7935c9f98ab Mon Sep 17 00:00:00 2001
From: Kenryu Shibata <kenryudev5894@gmail.com>
Date: Thu, 2 Jul 2026 10:29:57 +0900
Subject: [PATCH] added cls11

---
 report-cls11.tex   | 27 ++++++++++++++++
 src/cls11/Makefile | 14 ++++++++
 src/cls11/main.c   | 80 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 121 insertions(+)
 create mode 100644 report-cls11.tex
 create mode 100644 src/cls11/Makefile
 create mode 100644 src/cls11/main.c

diff --git a/report-cls11.tex b/report-cls11.tex
new file mode 100644
index 0000000..cc172bf
--- /dev/null
+++ b/report-cls11.tex
@@ -0,0 +1,27 @@
+\documentclass[xelatex,a4paper,11pt,ja=standard]{bxjsarticle}
+
+\usepackage{tex/preamble}
+\usepackage{tex/simple-title}
+
+\reportauthor{柴田健琉}
+\reporttitle{情報処理2 - 前期第11回課題}
+\reportdate{2026年}{07月}{02日}
+\turnindate{2026年}{07月}{06日}
+
+\begin{document}
+    \simpletitle
+
+    \section{はじめに}
+
+    この課題のプログラムは以下の環境での動作が確認されている:
+
+    \begin{itemize}
+        \item{OS: Arch Linux, Linux 6.18.37-1-lts x86\_64}
+        \item{CC: GCC 15.2.0}
+        \item{CFLAGS: \texttt{-g -O1 -Wall -Wpedantic}}
+    \end{itemize}
+
+    \section{課題 - 回文判定}
+
+
+\end{document}
diff --git a/src/cls11/Makefile b/src/cls11/Makefile
new file mode 100644
index 0000000..55e2aec
--- /dev/null
+++ b/src/cls11/Makefile
@@ -0,0 +1,14 @@
+include ../common.mk
+
+PROJECT_NAME:=cls11
+
+TGTS:=$(patsubst %.c,%,$(wildcard *.c))
+
+all: $(TGTS)
+
+%: %.c
+	@mkdir -p $(BUILD_PATH)/$(PROJECT_NAME)
+	$(CC) $(CFLAGS) $^ -o $(BUILD_PATH)/$(PROJECT_NAME)/$@
+
+clean:
+	$(RM) -drf $(BUILD_PATH)/$(PROJECT_NAME)
diff --git a/src/cls11/main.c b/src/cls11/main.c
new file mode 100644
index 0000000..38b79c8
--- /dev/null
+++ b/src/cls11/main.c
@@ -0,0 +1,80 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define BUFF_SZ 128
+
+// Lenght of string including null terminator
+int my_strlen(char *str, int max_len) {
+    int i = 0;
+    while (*(str + i) != '\0' && i < max_len)
+        i++;
+
+    return i;
+}
+
+// convert ASCII CAPITAL CASE ALPHABETS into lower case alphabets
+void to_lower(char *str, int sz) {
+    for (int i = 0; i < sz; i++) {
+        if (*(str + i) >= 'A' && *(str + i) <= 'Z') {
+            *(str + i) = *(str + i) + 0x20;
+        }
+    }
+}
+
+// remove every non-alphabet letters from string
+int strip(char *str, char *dest, int sz) {
+    int ret_sz = 0;
+
+    if (str == NULL || dest == NULL) {
+        return -1;
+    }
+
+    for (int i = 0; i < sz; i++) {
+        if (*(str + i) >= 'a' && *(str + i) <= 'z') {
+            *(dest + ret_sz) = *(str + i);
+            ret_sz++;
+        }
+    }
+
+    *(dest + ret_sz) = '\0';
+
+    return ret_sz;
+}
+
+// check if string is a palindrome
+bool kaibun(char *str, int sz) {
+    for (int i = 0; i < (sz - 1)/2; i++) {
+        if (*(str + i) != *(str + sz - i - 2)) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+int main(void) {
+    char *b = (char*)malloc(sizeof(char) * (BUFF_SZ + 1)); // BUFF_SZ letters + null terminator
+    char *t = (char*)malloc(sizeof(char) * (BUFF_SZ + 1));
+    
+    printf("Input string: ");
+    char* res = fgets(b, BUFF_SZ, stdin);
+    if (res == NULL) {
+        printf("Error while reading from stdin\n");
+        return 0;
+    }
+
+    int len = my_strlen(b, BUFF_SZ);
+
+    printf("len: %d\n", len);
+    
+    to_lower(b, len);
+    len = strip(b, t, len);
+
+    printf("len: %d\n", len);
+
+    bool isPalindrome = kaibun(t, len + 1);
+
+    printf("isPalindrome: %d\n", isPalindrome);
+
+    return 0;
+}