[Leetcode]-string to Integer (atoi)

Mplement 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.

Update (2015-02-10):
The signature of the C + + function had been updated. If you still see your function signature accepts a const char * argument, please click the reload button to reset your cod E definition.

Title: String to Integer
Note: There are a lot of details that need to be considered.
1, int overflow inference
2, sign, details see the main function
3, the case contains a space
Results: 4ms

#include <stdlib.h>#include <stdio.h>#include <math.h>#include <limits.h>intMyatoi (char* str) {//"NULL"  "000234"  "+23" " -34" "+-34"  "010"    if(NULL = = str)return 0;intsum =0.0;intf =0;intDIV = int_max/Ten; while(' + '!=*str)        {if(*str==' + ') {str++;if(*str<' 0 '||*str>' 9 ')return 0;Elsef =0; }if(*str=='-') {str++;if(*str<' 0 '||*str>' 9 ')return 0;Elsef =1; }if(*str>=' 0 '&&*str<=' 9 ')        {if(Sum > DIV && f = =0)returnInt_max;if(Sum > DIV && f = =1)return-int_max-1; sum = SUM *10.0;if(Int_max-*str+' 0 '< sum && F = =0)returnInt_max;if((Int_max-(*str-' 0 ') < sum) && (f = =1))return-int_max-1; sum = sum +*str-' 0 '; str++;if(*str==' + ') Break;Else if(*str<' 0 '||*str>' 9 ') Break; }Else{if(*str>=' A '&&*str<=' Z ') Break;        str++; }    }if(f) sum =-sum;returnsum;}intMain () {Char*str="0034";intR = Myatoi (str);printf("Myatoi str0 is: %d\ n", R); Char*STR1="XX";intR1 = Myatoi (str1);printf("Myatoi str1 is: %d\ n", R1); Char*STR2="+23";intr2 = Myatoi (str2);printf("Myatoi str2 is: %d\ n", r2); Char*STR3=" -2345";intR3 = Myatoi (STR3);printf("Myatoi STR3 is: %d\ n", R3); Char*STR4="+-23";intR4 = Myatoi (STR4);printf("Myatoi STR4 is: %d\ n", R4);//Expected0Char*STR5="010";intR5 = Myatoi (STR5);printf("Myatoi STR5 is: %d\ n", R5); Char*STR6="+0104";intR6 = Myatoi (STR6);printf("Myatoi STR6 is: %d\ n", R6); Char*STR7=" -0187";intR7 = Myatoi (STR7);printf("Myatoi STR7 is: %d\ n", R7);//Expected-187Char*str8=" -018a567";intR8 = Myatoi (STR8);printf("Myatoi str8 is: %d\ n", R8);//Expected- -Char*STR9="2147483648";intR9 = Myatoi (STR9);printf("Myatoi STR9 is: %d\ n", R9);//Expected2147483647Just take the maximum char because it's out of bounds*str10=" -2147483649";intR10= Myatoi (str10);printf("Myatoi Str10 is: %d\ n", R10);//Expected-2147483648Char*str11="-204";intR11 = Myatoi (STR11);printf("Myatoi Str11 is: %d\ n", R11);//Expected0Char*str12="b3424242";intR12 = Myatoi (str12);printf("Myatoi str12 is: %d\ n", R12);//Expected0       while(0);}

[leetcode]-string to Integer (atoi)