笔试题：09年_atoi

#include <stdio.h>#include <stdlib.h>//2009:写出一个字符串转换到整数的程序，例如输入:"-1234"，输出:-1234//思路:#define MININT 0xffffffff#define MAXSIZE 1024int my_atoi(const char* str,int iRadius = 10){//如果字符串为空，直接返回负的最大值if(NULL==str){return MININT;}int i = 0;bool isNegative = false;if('-' == str[i++]){isNegative = true;//设置负数标记}int sum = 0;char ch;for( ; (ch = str[i])!= '\0' ; i++){sum = sum*iRadius + (str[i] - '0');}return isNegative ? -1*sum : sum;}int main(int argc,char* argv[]){printf("请输输入你想要转换的字符串：");char str[MAXSIZE];scanf("%s",str);printf("\n转换后的数字是:%d",my_atoi(str));system("pause");getchar();return 0;}