itoa与atoi的实现

// my_itoa.cpp : Defines the entry point for the console application.//#include "stdafx.h"#include <stdio.h>#include <string.h>#include <stdlib.h>#include <ctype.h>//字符转化成整数int my_atoi(char s[]){//确定符号int i=0;for(i=0;isspace(s[i]);i++)//跳过空白;int sign=(s[i]=='-'?-1:1);if(s[i]=='+'||s[i]=='-')//跳过符号i++;//确定数值int n=0;for(;isdigit(s[i]);i++){n=n*10+(s[i]-'0');}return sign*n;}//整数转化成字符串void my_itoa(int n,char s[]){int sign=0;if((sign=n)<0)n=-n;int i=0;do {s[i++]=n%10+'0';//取下一个数字} while ((n/=10)>0);if (sign<0){s[i++]='-';}s[i]='/0';int j=0;for(j=i;j>=0;j--){printf("%c",s[j]);}printf("/n");}int main(int argc, char* argv[]){char s[]=" -23231345";int res=my_atoi(s);printf("%d/n",res);int num=-125654;char *a=(char*)calloc(sizeof(char),1000);my_itoa(num,a);return 0;}