LeetCode 8

String to Integer (atoi)

Implement atoi to convert a string to an integer.

 

/*************************************************************************
    > File Name: LeetCode008.c
    > Author: Juntaran 
    > Mail: Jacinthmail@gmail.com
    > Created Time: 2016年04月24日 星期日 15时51分05秒
 ************************************************************************/
 
/*************************************************************************

    Implement atoi to convert a string to an integer.

 ************************************************************************/
 
#include <stdio.h>
#include <limits.h>

int myAtoi(char* str) {

    int flag = 1;
    long sum = 0;

    while( *str == ' ' ){
        str++;
    }
    
    if ( *str == '+' || *str == '-' ){
        flag = (*str++ == '+' ? 1 : -1 );
    }

    while( isdigit(*str) && sum < INT_MAX ){
        sum = 10*sum + (*str++ - '0');
    }
    if( flag == 1 ){
        sum = sum > INT_MAX ? INT_MAX : sum;
        printf("%d\n",sum);
        return  sum;
    }else{
        sum = (sum *= flag) < INT_MIN ? INT_MIN : sum;
        printf("%d\n",sum);
        return  sum;
    }

}

int main(){
    
    char* str = "-100.ab";
    myAtoi(str);
}