实现函数 int32_t my_strtoint32(const string& str), 将一个10进制的ASCII码字符串转换成 int32_t,支持正负号,字符串前后请允许空格, 数字串可以有前置0 `12345 == my_strtoint32("12345");`
#define UINT32_MAX 0xffffffff
#define EINVAL 22 #define ERANGE 34 ``` ``` 返回值与错误码参照 <stdlib.h> strtol 说明 Return Value The strtol() function returns the result of the conversion, unless the value would underflow or overflow. If an underflow occurs, strtol() returns LONG_MIN. If an overflow occurs, strtol() returns LONG_MAX. In both cases, errno is set to ERANGE. Errors EINVAL, The given base contains an unsupported value. ERANGE, The resulting value was out of range. ``` </stdlib.h>