#include using namespace std; /* run this program using the console pauser or add your own getch, system("pause") or input loop */ int main(int argc, char** argv) { //1.C++ 字串 成員函式 //(1)char& at (size_t pos); / [ ] string s1 = "happy birthday"; char c1 = s1.at(0); cout<<"s1.at(0) = "<at(4); cout<<"s2->at(4) = "<size() = "<