#include<iostream>
using namespace std;

void addFive(int Number){
    
    
	Number = Number + 5;
} 

int main(){
    
    
	int nMyNumber = 18; 
	cout<<"My original number is "<<nMyNumber<<endl;
	addFive(nMyNumber);//此处传递的是nMyNumber的一个副本
//	因此+5的也是副本，main中的nMyNumber没变 
	cout<<"My new number is "<<nMyNumber ;
	return 0; 
//最后结果无法输出23
}
 

#include<iostream>
using namespace std;

void addFive(int *Number){
    
    //Number前加*号
//是为了告诉编译器，们是指针所指的变量＋5，不是指针自己+5
	*Number = *Number + 5;
} 

int main(){
    
    
	int nMyNumber = 18; 

	cout<<"My original number is "<<nMyNumber<<endl;
	
	addFive(&nMyNumber);

	cout<<"My new number is "<<nMyNumber ;
	return 0; 
}