atoi

10分钟手写atoi函数

int atoi(const char str[])

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

}