字符串和整数的快速转换

将字符串转换为整数

#include<iostream>
#include<sstream>
#include<string>
using namespace std;
void schangei(int &n,string &s) {
	stringstream ss;
	ss << s;
	ss >> n;
}
int main() {
	int n;
	string s;
	cin >> s;
	schangei(n, s);
	cout << n + 100 << endl;
	return 0;
}

这是可以运行的，我们输入的是一个字符串，s里面的字符串被转换成整数存储在n中 ,下面介绍另一种写法将s字符串转为整数作为函数的返回值

#include<iostream>
#include<sstream>
#include<string>
using namespace std;
int schangei(string s) {
	int n;
	stringstream ss;
	ss << s;
	ss >> n;
	return n;
}
int main() {
	int n;
	string s;
	cin >> s;
	n = schangei(s);
	cout << n + 100 << endl;
	return 0;
}

上面两个输入100 输出200

将整数转换为字符串

#include<iostream>
#include<sstream>
#include<string>
using namespace std;
void ichanges(int &n, string &s) {
	stringstream ss;
	ss << n;
	ss >> s;
}
int main() {
	int n;
	string s;
	cin >> n;
	ichanges(n, s);
	cout << s+ "100" << endl;
	return 0;
}

另一种写法

#include<iostream>
#include<sstream>
#include<string>
using namespace std;
string ichanges(int n) {
	stringstream ss;
	string s;
	ss << n;
	ss >> s;
	return s;
}
int main() {
	int n;
	string s;
	cin >> n;
	s=ichanges(n);
	cout << s+ "100" << endl;
	return 0;
}

输入100输出100100