3 strings

1 String (String) be a finite sequence of zero or more characters.

Custom function to achieve a 1.1 to Integer String function

Special cases

1. Blank header can be excluded, counted from the first non-blank character
2. In allowing the digital sign (+ -) at the beginning of
3. Encounter illegal characters will stop the conversion, returns the current value has been converted, if that is the beginning of the illegal character returns 0
4. Returns a specific value at the conversion result overflows, this is the largest / smallest integer

Test Case

　　" 010"，" +004500"，" -001+2a42"，" +0 123" ，"-2147483648"， "2147483648"，

　　" - 321"， " -11919730356x" ，"9223372036854775809"

Correct output

　　10，4500，-1 ，0，-2147483648，2147483647，0，-2147483648，2147483647