atoi与itoa代码实现

#include<iostream>#include<stdio.h>using namespace std;void main(){int num=-12345,j=0,i=0;char temp[7],str[7];if(num<0){temp[i]='-';i++;}num=abs(num);while(num){temp[i]=num%10+'0';i++;num/=10;}temp[i]=0;i--;if(temp[0]=='-'){str[j++]=temp[0];while(i>0){str[j]=temp[i];j++;i--;}}else{while(i>=0){str[j]=temp[i];j++;i--;}}str[j]=0;cout<<str<<endl;int numb=-34567;char strs[7];itoa(numb,strs,10);cout<<strs<<endl;/*---------------atoi--------------*/char *ch="123456";//不包含负数情况int chi=0,tempnum=0;while(chi<strlen(ch)){tempnum=tempnum*10+ ch[chi++]-'0';}cout<<"tempnum="<<tempnum<<endl;int sumtemp=0;cout<<"atoi="<<atoi(ch)<<endl;system("pause");}