写一个atoi函数

写一个Atoi函数，实现字符串转换成整型数字

int MyAtoi(const char *p){int result = 0;int flag = 1;if (*p == '-' || *p == '+' || (*p >= '0'&&*p <= '9')){if (*p == '-'){flag = -1;p++;}else if (*p == '+'){p++;}while (*p >= '0' && *p <= '9'){result = 10 * result + *p++ - '0';}}return flag*result;}