基於範圍的for迴圈
阿新 • • 發佈:2018-12-11
1)語法:for(decl : coll){//statement}
①decl用於宣告元素及型別,如int elem或auto elem(讓編譯器自動推導集合中元素的型別),但應注意auto& elem和auto elem的區別,前者是元素的引用,後者是元素的副本。
②coll為元素的集合
注意auto& elem和auto elem的區別
int ar[3] = {1,2,3};
for (int e:ar) {//注意auto& elem和auto elem的區別,前者是元素的引用,後者是元素的副本
e += 2;
cout << e <<" ";
}cout <<endl;
for (int i = 0; i < 3; i++) {
cout << ar[i]<<" ";
}cout << endl;
int ar[3] = {1,2,3};
for (int &e:ar) {//注意auto& elem和auto elem的區別,前者是元素的引用,後者是元素的副本
e += 2;
cout << e <<" ";
}cout <<endl;
for (int i = 0; i < 3; i++) {
cout << ar[i]<<" ";
}cout << endl;