Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
470 views
in Technique[技术] by (71.8m points)

pointer to array c++

What is the following code doing?

int g[] = {9,8};
int (*j) = g;

From my understanding its creating a pointer to an array of 2 ints. But then why does this work:

int x = j[0];

and this not work:

int x = (*j)[0];
See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

The parenthesis are superfluous in your example. The pointer doesn't care whether there's an array involved - it only knows that its pointing to an int

  int g[] = {9,8};
  int (*j) = g;

could also be rewritten as

  int g[] = {9,8};
  int *j = g;

which could also be rewritten as

  int g[] = {9,8};
  int *j = &g[0];

a pointer-to-an-array would look like

  int g[] = {9,8};
  int (*j)[2] = &g;

  //Dereference 'j' and access array element zero
  int n = (*j)[0];

There's a good read on pointer declarations (and how to grok them) at this link here: http://www.codeproject.com/Articles/7042/How-to-interpret-complex-C-C-declarations


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...