"Leetcode-Interview algorithm classic-java Implementation" "008-string to Integer (atoi) (String to Integer)"

"008-string to Integer (Atoi) (string converted to integer)" "leetcode-Interview algorithm classic-java Implementation" "All Topics folder Index" Original Question

Implement atoi to convert a string to an integer.
Hint:carefully consider all possible input cases. If you want a challenge, please don't see below and ask yourself what is the possible input cases.
Notes:it is intended-problem to be specified vaguely (ie, no given input specs). You is responsible to gather all the input requirements up front.

Main Topic

Implement a Atoi function to convert a string into an orthopedic
Important: Consider the full input situation.

Thinking of solving problems

The leading character is + or-or not. The next step is to enter a number, and the number cannot be the maximum or the decimal that the integer can represent. Assume that the corresponding minimum or minimum value is returned.

Code Implementation

 Public  class solution {     Public intAtoi (StringStr) {if(Str==NULL||Str. Length () = =0) {//throw new NumberFormatException ("Invalid input string:" + str);            return 0; }//Suppose the string starts with a space        intStart =0;//Start looking for the first number that is not a space        BooleanPositive =true;//Whether it is positive to feel true        if(Str. charAt (start) = ="') { while(Str. charAt (start) = ="') {start++;if(Start >=Str. Length ()) {//input is full of spaces//throw new NumberFormatException ("Invalid input string:" + str);                    return 0; }            }        }if(Str. charAt (start) = ='-') {//First non-whitespace character-Positive =false;        start++; }Else if(Str. charAt (start) = =' + ') {//The first non-whitespace character is +start++; }Else if(Str. CharAt (Start) >=' 0 '&&Str. CharAt (Start) <=' 9 ') {//The first non-whitespace character is a number            returnCalStr, Start,true); }Else{//Other cases throw an exception//throw new NumberFormatException ("Invalid input string:" + str);            return 0; }if(Start >=Str. Length ()) {//The first non-whitespace character is + or-but also the last character//throw new NumberFormatException ("Invalid input string:" + str);            return 0; }if(Str. CharAt (Start) >' 9 '||Str. charAt (Start) <' 0 ') {//+ or-not the number followed//throw new NumberFormatException ("Invalid input string:" + str);            return 0; }Else{returnCalStr, start, positive); }    }Private intCal (StringStr,intStartBooleanPositive) {Longresult =0; while(Start <Str. Length () &&Str. CharAt (Start) >=' 0 '&&Str. CharAt (Start) <=' 9 ') {result = result *Ten+ (Str. CharAt (Start)-' 0 ');if(positive) {//assumed to be positive                if(Result > Integer.max_value) {//throw new NumberFormatException ("Invalid input string:" + str);                    returnInteger.max_value; }            }Else{if(-result < Integer.min_value) {//throw new NumberFormatException ("Invalid input string:" + str);                    returnInteger.min_value;        }} start++; }if(positive) {return(int) result; }Else{return(int)-result; }    }}

Assessment Results

　　Click on the picture, the mouse does not release. Drag a position to view the full picture in the new form after you release it.

Special Instructions Welcome reprint, Reprint please indicate the source "http://blog.csdn.net/derrantcm/article/details/46938417"

"Leetcode-Interview algorithm classic-java Implementation" "008-string to Integer (atoi) (String to Integer)"