[Microsoft面试]题目：输入一个表示整数的字符串，把该字符串转换成整数并输出。

例如输入字符串"345"，则输出整数345。

Thisquestion checks how the interviewee is familiar with C/C++? I’m so bad atC/C++...intatoi(char * str) {  int neg = 0;  char * p = str;  if (*p == ‘-’) {    p++; neg = 1;  } else if (*p == ‘+’) {    p++;  }  int num = 0;  while (*p != ‘\0’) {    if (*p>='0' && *p <= '9') {      num = num * 10 + (*p-’0’);    } else {      error(“illegal number”);    }    p++;  }  return num;}PS: I didn’t figure out how to tell a overflow problem easily.