8

include/solution/8.h

@@ -0,0 +1,14 @@
+// This file is generated by mkfile.py
+// Date: 2026-06-25
+
+#ifndef INC_8_H
+#define INC_8_H
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+    int myAtoi(char *s);
+#ifdef __cplusplus
+}
+#endif
+#endif // INC_8_H

src/8.c

@@ -0,0 +1,58 @@
+// This file is generated by mkfile.py
+// Date: 2026-06-25
+
+#include <solution/8.h>
+
+#include <limits.h>
+#include <stdbool.h>
+int myAtoi(char *s)
+{
+    long ret = 0;
+    int length = 0;
+    bool isPos = true;
+    bool hasSign = false;
+    bool hasDigit = false;
+    bool hasSpace = true;
+
+    for (; *s != '\0' && length < 11; s++)
+    {
+        // step 1 skip space
+        if (hasSpace)
+        {
+            if (*s == ' ')
+                continue;
+            hasSpace = false;
+        }
+        // step 2 check is sign while has no number
+        if (!hasDigit && !hasSign && (*s == '-' || *s == '+'))
+        {
+            hasSign = true;
+            isPos = *s == '+';
+            continue;
+        }
+        // step 3 read num
+        if (*s - '0' >= 0 && *s - '9' <= 0)
+        {
+            hasDigit = true;
+            // check if front zero
+            if (length == 0 && *s == '0')
+                continue;
+
+            // not front zero
+            if (length > 0)
+                ret *= 10;
+            ret += *s - '0';
+            length++;
+            continue;
+        }
+        // step 4 check char
+        break;
+    }
+
+    if (isPos)
+        ret = ret > INT_MAX ? INT_MAX : ret;
+    else
+        ret = ret * -1 < INT_MIN ? INT_MIN : ret * -1;
+
+    return (int)ret;
+}

tests/test_8.cpp

@@ -0,0 +1,87 @@
+// This file is generated by mkfile.py
+// Date: 2026-06-25
+
+#include <gtest/gtest.h>
+#include <solution/8.h>
+
+#include <climits>
+#include <string>
+#include <vector>
+
+class MyAtoiTest : public ::testing::Test
+{
+  protected:
+    void AssertMyAtoi(const std::string &input, int expected)
+    {
+        std::vector<char> buffer(input.begin(), input.end());
+        buffer.push_back('\0');
+
+        EXPECT_EQ(myAtoi(buffer.data()), expected);
+    }
+};
+
+TEST_F(MyAtoiTest, Example1)
+{
+    AssertMyAtoi("42", 42);
+}
+
+TEST_F(MyAtoiTest, Example2)
+{
+    AssertMyAtoi("   -42", -42);
+}
+
+TEST_F(MyAtoiTest, Example3)
+{
+    AssertMyAtoi("4193 with words", 4193);
+}
+
+TEST_F(MyAtoiTest, ReturnsZeroWhenStringStartsWithNonDigit)
+{
+    AssertMyAtoi("words and 987", 0);
+}
+
+TEST_F(MyAtoiTest, ReadsOptionalPlusSign)
+{
+    AssertMyAtoi("+1", 1);
+}
+
+TEST_F(MyAtoiTest, RejectsMultipleOrSeparatedSigns)
+{
+    AssertMyAtoi("+-12", 0);
+    AssertMyAtoi("-+12", 0);
+    AssertMyAtoi("   +  413", 0);
+}
+
+TEST_F(MyAtoiTest, StopsAtFirstNonDigitAfterReadingDigits)
+{
+    AssertMyAtoi("3.14159", 3);
+    AssertMyAtoi("00000-42a1234", 0);
+    AssertMyAtoi("  +0 123", 0);
+}
+
+TEST_F(MyAtoiTest, HandlesEmptyAndSignOnlyStrings)
+{
+    AssertMyAtoi("", 0);
+    AssertMyAtoi("   ", 0);
+    AssertMyAtoi("+", 0);
+    AssertMyAtoi("-", 0);
+}
+
+TEST_F(MyAtoiTest, ClampsPositiveOverflow)
+{
+    AssertMyAtoi("2147483647", INT_MAX);
+    AssertMyAtoi("2147483648", INT_MAX);
+    AssertMyAtoi("91283472332", INT_MAX);
+}
+
+TEST_F(MyAtoiTest, ClampsNegativeOverflow)
+{
+    AssertMyAtoi("-2147483648", INT_MIN);
+    AssertMyAtoi("-2147483649", INT_MIN);
+    AssertMyAtoi("-91283472332", INT_MIN);
+}
+
+TEST_F(MyAtoiTest, IgnoresLeadingZerosBeforeValidDigits)
+{
+    AssertMyAtoi("  0000000000012345678", 12345678);
+}