The main difference between pointer and reference

The pointer “ Point to ” An object in memory , And quote “ Bound to the ” An object in memory , They all implement indirect access to other objects , There are two main differences between the two :

First of all , The pointer itself is an object , Allows assignment of values and values to pointers , And in the life cycle of the pointer, it can point to several different objects ; Reference is not an object , Cannot rebind reference to another object .

second , The pointer does not need to have an initial value at definition time , Like other built-in types , If a pointer defined within the scope of a block is not initialized , Will also have an uncertain value ; The reference must be given an initial value at the time of definition .

The code is ：

#include<iostream>
using namespace std;
void swap1(int &a,int &b){ // Reference implementation 
	int temp=0;
	temp = a;
	a = b;
	b = temp;
};

void swap2(int *a,int *b){  // Pointer implementation 
	int temp=0;
	temp = *a;
	*a = *b;
	*b = temp;
};

int main(){
	int i=5,j=10;
	int*p=&i;
	cout<<p<<"\t"<<*p<<endl;
	p=&j;
	cout<<p<<"\t"<<*p<<endl;
	*p=20;
	cout<<p<<"\t"<<*p<<endl;
	j=30;
	cout<<p<<"\t"<<*p<<endl;
	
	swap1(i,j);
	cout<<i<<"\t"<<j<<endl;
	cout<<p<<"\t"<<*p<<endl;
	swap2(&i,&j);
	cout<<i<<"\t"<<j<<endl;
	cout<<p<<"\t"<<*p<<endl;
	return 0;
} 

Output results ：

0x66ff24        5
0x66ff20        10
0x66ff20        20
0x66ff20        30
30      5
0x66ff20        5
5       30
0x66ff20        30
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