常用的头文件

1. printf,snprintf

need #include <stdio.h>

2. cout and cin

#include <iostream.h>
using namespace std;

3. accept string using cin

#include <iostream>
#include <string> // or #include "string.h"
using namespace std;

int main() {

 string input = "";

 // How to get a string/sentence with spaces
 cout << "Please enter a valid sentence (with spaces):\n>";
 getline(cin, input);
 cout << "You entered: " << input << endl << endl;
}