const vector<type>v 这个定义等于是废的,因为都不允许指针指向下一个地址,所以是废的。
vector<type>::const_iterator 并不是const与iterator的简单叠加,const_iterator允许指向下一个地址,可以遍历整个容器,但是不允许修改*iter.
#include<iostream> #include<string> #include<vector> using namespace std; int main(){ int a; vector<int>v; while(cin>>a){ v.push_back(a); } for(vector<int>::size_type i=0;i<v.size();i++){ cout<<v[i]<<" "; } cout<<endl; for(vector<int>::iterator iter=v.begin();iter!=v.end();iter++){ *iter=20; } for(vector<int>::iterator iter1=v.begin();iter1!=v.end();iter1++){ cout<<*iter1<<" "; } cout<<endl; return 0; }
#include<iostream> #include<string> #include<vector> using namespace std; int main(){ int a; vector<int>v; while(cin>>a){ v.push_back(a); } for(vector<int>::const_iterator iter=v.begin();iter!=v.end();iter++){ *iter=10; } for(vector<int>::const_iterator iter1=v.begin();iter1!=v.end();iter1++){ cout<<*iter1<<" "; } cout<<endl; return 0; }
#include<iostream> #include<string> #include<vector> using namespace std; int main(){ string s; const vector<string>v; while(cin>>s){ v.push_back(s); //错误 } for(vector<string>::iterator iter=v.begin();iter!=v.end();iter++){//错误,不允许改变指针地址 cout<<*iter<<" "; } return 0; }