1.int转字符串字符串转int?

例:"123"123

#include<iostream>
#include<string>
using namespace std;string string_head_end(string str) {string s="";for (int i = str.length()-1; i >= 0; i--) {s += str[i];}return s;
}
string int_to_string(int value) {string str="";while (value % 10) {char c = value % 10 + '0';str += c;value /= 10;}return string_head_end(str);
}int string_to_int(string str) {int result = 0;for (int i = 0; i < str.length(); i++) {char c = str[i];int value = c - '0';result = result*10 + value;}return result;
}int main() {int value = 122234;string str = int_to_string(value);int result;result = string_to_int(str);cout << str << endl;cout << result << endl;return 0;
}

2.strcat,strcpy,strncpy,memset,memcpy的内部实现？

实现
实现