[問題] STL iterator 在 for 中慣用法
遇到要列舉一容器(如vector)中的元素時
我看過的書都建議這樣…
(A)
for ( vector<myType>::iterator iter = myVect.begin();
iter != myVect.end();
++iter )
{
...
iter->xxx // blahblah
...
}
而不要寫成
(B)
for ( unsigned i = 0; i < myVect.size(); ++i )
{
...
myVect[i].xxx // blahblah
...
}
當然 map set等一定要用A
但vector中 我反而覺得A寫得很囉嗦
萬一在for主體又想取得索引值(i的值)時，
又很麻煩 (把iter - myVect.begin() ) 或者干脆用B的寫法
效率上也許 iter->xxx 比 myVect[i].xxx 快
後者多一個i的加法??
請問A的寫法還有什麼優點呢？
感謝！
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