for(int i:a)的意思

#include 
#include 
#include 

using namespace std;

int main(void) {
	vector a = {3, 1, 2, 4};
	for(int i: a) {
		cout << i << " ";
	}
	cout << endl;
	int aa[] = {1, 3, 4, 2};
	for(int i: aa) {
		cout << i << " ";
	}
	cout << endl;
	char c[20];
	for(int i = 0; i < 20; ++i){
		*(c + i) = 'a' + i;
	}
	for(char i: c){
		cout << i << " ";
	}
	cout << endl;
	string s[] = {"Hello" , "World!", "My", "name", "is", "Zhi Qiang", "Welcome", "to"};
	for(string i:s) {
		cout << i << endl;
	}
	cout << endl;
}