stringstream快速实现String和int之间的转换

需要包含头文件”sstream”

#include <iostream>
#include <string>
#include <sstream>
using namespace std;
int string2int(string str){
    int num;
    stringstream sstream;
    sstream << str;
    sstream >> num;
    return num;
}
string int2string(int num){
    string re;
    stringstream sstream;
    sstream << num;
    return sstream.str();
}