atoi与itoa的C++实现

int atoiTest(char s[])
{
int i=0,sum=0,sign;
while(' '==s[i]||'\t'==s[i])
{
i++;
}
sign=('-'==s[i])?-1:1;
if('-'==s[i]||'+'==s[i])
i++;
while(s[i]!='\0')
{
sum=s[i]-'0'+sum*10;
i++;
}
return sign*sum;
}

void itoaTest(int num,char str[])
{
int sign=num,i=0,j=0;
char temp[11];
if(sign<0)
{
num=-num;
}
do
{
temp[i]=num%10+'0';
num/=10;
i++;
}while(num>0);
if(sign<0)
{
temp[i++]='-';
}
temp[i]='\0';
i--;
while(i>=0)
{
str[j]=temp[i];
j++;
i--;
}
str[j]='\0';

}

http://c.chinaitlab.com/c/basic/200902/776622.html