diff --git a/boot.c b/boot.c
index db14a1c..bfab8ac 100644
--- a/boot.c
+++ b/boot.c
@@ -230,25 +230,15 @@ int parse_int(int ch) {
 
 int get_escaped_char() {
     int ch = getchar();
-    if (ch == 'n') {
-        ch = '\n';
-    } else if (ch == 't') {
-        ch = '\t';
-    } else if (ch == 'r') {
-        ch = '\r';
-    } else if (ch == '0') {
-        ch = '\0';
-    } else if (ch == '\\') {
-        ch = '\\';
-    } else if (ch == '\'') {
-        ch = '\'';
-    } else if (ch == '\"') {
-        ch = '\"';
-    } else {
-        fprintf(stderr, "unexpected escaped character: '\\%c'\n", ch);
-        exit(1);
-    }
-    return ch;
+    if (ch == 'n') return '\n';
+    if (ch == 't') return '\t';
+    if (ch == 'r') return '\r';
+    if (ch == '0') return '\0';
+    if (ch == '\\') return '\\';
+    if (ch == '\'') return '\'';
+    if (ch == '\"') return '\"';
+    fprintf(stderr, "unexpected escaped character: '\\%c'\n", ch);
+    exit(1);
 }
 
 int token_state;
diff --git a/demo/queen.c b/demo/queen.c
index 855793e..66463b5 100644
--- a/demo/queen.c
+++ b/demo/queen.c
@@ -30,6 +30,7 @@ void queen(int x) {
     if (x > 8) {
         output();
         a[0]++;
+        return;
     }
     for (int y = 1; y <= 8; ++y) {
         if (ok(x, y)) {
diff --git a/demo/sort.c b/demo/sort.c
new file mode 100644
index 0000000..21ac5a6
--- /dev/null
+++ b/demo/sort.c
@@ -0,0 +1,36 @@
+int printf(char* format, ...);
+int scanf(char* format, ...);
+int exit(int status);
+
+void swap(int* a, int* b) {
+    int t = *a;
+    *a = *b;
+    *b = t;
+}
+
+void sort(int a[], int n) {
+    for (int i = 0; i < n; i++) {
+        for (int j = i + 1; j < n; j++) {
+            if (a[i] > a[j]) {
+                swap(&a[i], &a[j]);
+            }
+        }
+    }
+}
+
+int a[100];
+int n;
+
+int main() {
+    printf("Enter the number of elements: ");
+    scanf("%d", &n);
+    printf("Enter %d integers: ", n);
+    for (int i = 0; i < n; i++) {
+        scanf("%d", &a[i]);
+    }
+    sort(a, n);
+    for (int i = 0; i < n; i++) {
+        printf("%d ", a[i]);
+    }
+    printf("\n");
+}
\ No newline at end of file
diff --git a/run.sh b/run.sh
index e07d810..1481d3d 100644
--- a/run.sh
+++ b/run.sh
@@ -14,4 +14,4 @@ gcc boot.c -o boot.elf &&
 ./boot.elf < $1 > $1.s &&
 compile_and_run $1
 echo $?
-rm $1.s $1.s.elf boot.elf 2> /dev/null
\ No newline at end of file
+rm $1.s $1.elf boot.elf 2> /dev/null
\ No newline at end of file
diff --git a/test/function/hanoi.c b/test/function/hanoi.c
new file mode 100644
index 0000000..8f9382f
--- /dev/null
+++ b/test/function/hanoi.c
@@ -0,0 +1,20 @@
+int printf(char* format, ...);
+
+void move(char from_rod, char to_rod) {
+    printf("%c --> %c\n", from_rod, to_rod);
+}
+
+void hanoi(int n, char from_rod, char to_rod, char aux_rod) {
+    if (n == 1) {
+        move(from_rod, to_rod);
+        return;
+    }
+    hanoi(n - 1, from_rod, aux_rod, to_rod);
+    move(from_rod, to_rod);
+    hanoi(n - 1, aux_rod, to_rod, from_rod);
+}
+
+int main() {
+    int n = 3;
+    hanoi(n, 'A', 'C', 'B');
+}
\ No newline at end of file
diff --git a/test/function/hanoi.out b/test/function/hanoi.out
new file mode 100644
index 0000000..4fe7fc8
--- /dev/null
+++ b/test/function/hanoi.out
@@ -0,0 +1,8 @@
+A --> C
+A --> B
+C --> B
+A --> C
+B --> A
+B --> C
+A --> C
+0
diff --git a/test/function/queen.c b/test/function/queen.c
new file mode 100644
index 0000000..2bac9b0
--- /dev/null
+++ b/test/function/queen.c
@@ -0,0 +1,32 @@
+int printf(char* format, ...);
+int putchar(int ch);
+
+int a[9];
+
+int ok(int x, int y) {
+    for (int i = 1; i <= x - 1; ++i) {
+        if (a[i] == y || a[i] - i == y - x || a[i] + i == y + x) {
+            return 0;
+        }
+    }
+    return 1;
+}
+
+void queen(int x) {
+    if (x > 8) {
+        a[0]++;
+        return;
+    }
+    for (int y = 1; y <= 8; ++y) {
+        if (ok(x, y)) {
+            a[x] = y;
+            queen(x + 1);
+            a[x] = 0;
+        }
+    }
+}
+
+int main() {
+    queen(1);
+    printf("%d\n", a[0]);
+}
\ No newline at end of file
diff --git a/test/function/queen.out b/test/function/queen.out
new file mode 100644
index 0000000..0af0bb6
--- /dev/null
+++ b/test/function/queen.out
@@ -0,0 +1,2 @@
+92
+0
diff --git a/test/io/echo.c b/test/io/echo.c
new file mode 100644
index 0000000..b850415
--- /dev/null
+++ b/test/io/echo.c
@@ -0,0 +1,7 @@
+int getchar();
+int putchar(int ch);
+
+int main() {
+    for (char ch; (ch = getchar()) != -1; putchar(ch));
+    putchar('\n');
+}
\ No newline at end of file
diff --git a/test/io/echo.in b/test/io/echo.in
new file mode 100644
index 0000000..95d09f2
--- /dev/null
+++ b/test/io/echo.in
@@ -0,0 +1 @@
+hello world
\ No newline at end of file
diff --git a/test/io/echo.out b/test/io/echo.out
new file mode 100644
index 0000000..ff8fbcb
--- /dev/null
+++ b/test/io/echo.out
@@ -0,0 +1,2 @@
+hello world
+0
diff --git a/test/misc/escape.c b/test/io/escape.c
similarity index 64%
rename from test/misc/escape.c
rename to test/io/escape.c
index 92cf816..f04ce79 100644
--- a/test/misc/escape.c
+++ b/test/io/escape.c
@@ -1,14 +1,16 @@
-int getchar();
-int putchar(int ch);
-int fprintf(void* file, char* format, ...); 
-extern void* stdout;
+int offset = 0;
 
+int get() {
+    return "hello\\n\\tworld\\\\\\'\\\"\\0\r\t\0"[offset++];
+}
+
+int putchar(int ch);
 
 int main() {
-    char ch = 0["\t\r\""];;
-    while ((ch = getchar()) != -1) {
+    char ch;
+    while ((ch = get()) != 0) {
         if (ch == '\\') {
-            ch = getchar();
+            ch = get();
             if (ch == 'n') {
                 ch = '\n';
             } else if (ch == 't') {
@@ -16,7 +18,7 @@ int main() {
             } else if (ch == 'r') {
                 ch = '\r';
             } else if (ch == '0') {
-                ch = '\0';
+                break;
             } else if (ch == '\\') {
                 ch = '\\';
             } else if (ch == '\'') {
@@ -24,8 +26,7 @@ int main() {
             } else if (ch == '\"') {
                 ch = '\"';
             } else {
-                fprintf(stdout, "unexpected escaped character: '\\%c'\n", ch);
-                return 1;
+                break;
             }
         }
         putchar(ch);
diff --git a/test/io/escape.out b/test/io/escape.out
new file mode 100644
index 0000000..6354775
--- /dev/null
+++ b/test/io/escape.out
@@ -0,0 +1,2 @@
+hello
+	world\'"0
diff --git a/test/io/extern.c b/test/io/extern.c
new file mode 100644
index 0000000..c9fa893
--- /dev/null
+++ b/test/io/extern.c
@@ -0,0 +1,16 @@
+int fprintf(void* stream, char* format, ...);
+int fscanf(void* stream, char* format, ...);
+int sprintf(char* str, char* format, ...);
+
+extern void* stdin;
+extern void* stdout;
+
+int main() {
+    char buffer[4096];
+    int a;
+    int b;
+    fscanf(stdin, "%d %d", &a, &b);
+    sprintf(buffer, "The sum of %d and %d is %d\n", a, b, a + b);
+    fprintf(stdout, buffer);
+    return 0;
+}
\ No newline at end of file
diff --git a/test/io/extern.in b/test/io/extern.in
new file mode 100644
index 0000000..e7e7d8e
--- /dev/null
+++ b/test/io/extern.in
@@ -0,0 +1 @@
+3 4
\ No newline at end of file
diff --git a/test/io/extern.out b/test/io/extern.out
new file mode 100644
index 0000000..e64d8a1
--- /dev/null
+++ b/test/io/extern.out
@@ -0,0 +1,2 @@
+The sum of 3 and 4 is 7
+0
diff --git a/test/loop/diamond.c b/test/loop/diamond.c
new file mode 100644
index 0000000..4d9bf15
--- /dev/null
+++ b/test/loop/diamond.c
@@ -0,0 +1,30 @@
+int printf(char* format, ...);
+
+
+int main() {
+    int n = 5; // height of the diamond
+    int i;
+    int j;
+
+    // upper half of the diamond
+    for (i = 1; i <= n; i++) {
+        for (j = i; j < n; j++) {
+            printf(" ");
+        }
+        for (j = 1; j <= (2 * i - 1); j++) {
+            printf("*");
+        }
+        printf("\n");
+    }
+
+    // lower half of the diamond
+    for (i = n - 1; i >= 1; i--) {
+        for (j = n; j > i; j--) {
+            printf(" ");
+        }
+        for (j = 1; j <= (2 * i - 1); j++) {
+            printf("*");
+        }
+        printf("\n");
+    }
+}
\ No newline at end of file
diff --git a/test/loop/diamond.out b/test/loop/diamond.out
new file mode 100644
index 0000000..d369f75
--- /dev/null
+++ b/test/loop/diamond.out
@@ -0,0 +1,10 @@
+    *
+   ***
+  *****
+ *******
+*********
+ *******
+  *****
+   ***
+    *
+0
diff --git a/test/loop/nested.c b/test/loop/nested.c
deleted file mode 100644
index 6232e27..0000000
--- a/test/loop/nested.c
+++ /dev/null
@@ -1,20 +0,0 @@
-int printf(char* format, ...);
-
-void test() {
-    int i; 
-    int j;
-
-    for (i = 0; i < 5; i++) {
-        for (j = 0; j < 5; j++) {
-            if (i >= 2 && j >= 2 && i + j >= 5) {
-                return; // Exit nested loop via return
-            }
-            printf("(%d, %d)%c", i, j, " \n"[j == 4]);
-        }
-    }
-}
-
-int main() {
-    test();
-    printf("\n");
-}
\ No newline at end of file
diff --git a/test/loop/nested.out b/test/loop/nested.out
deleted file mode 100644
index bea6ce1..0000000
--- a/test/loop/nested.out
+++ /dev/null
@@ -1,4 +0,0 @@
-(0, 0) (0, 1) (0, 2) (0, 3) (0, 4)
-(1, 0) (1, 1) (1, 2) (1, 3) (1, 4)
-(2, 0) (2, 1) (2, 2) 
-0
diff --git a/test/misc/escape.in b/test/misc/escape.in
deleted file mode 100644
index 0ee2bcc..0000000
--- a/test/misc/escape.in
+++ /dev/null
@@ -1 +0,0 @@
-hello\n\tworld\u
\ No newline at end of file
diff --git a/test/misc/escape.out b/test/misc/escape.out
deleted file mode 100644
index 3230064..0000000
--- a/test/misc/escape.out
+++ /dev/null
@@ -1,3 +0,0 @@
-hello
-	worldunexpected escaped character: '\u'
-1