如何从动态分配的数组中删除元素？

我有一个动态分配的数组：如何从动态分配的数组中删除元素？

myRectangle lastRectanglesArray = new myRectangle[lastMaxLabel];

我想通过这个阵列中的所有元素循环和消除这些能够满足我的条件（例如过大的矩形）。

我一直在想，我可以遍历这个数组，并获得满足我的条件的元素数量，然后分配一个新的数组。但是，如何将这些“想要的”元素“转移”到我的新阵列中？

只是为了记录：我不能使用STL容器。

来源

2012-02-12 Patryk

我想你在你最后一句话中意外地用了一个词。 – 2012-02-12 03:26:20

只是可能有一个缺失 – 2012-02-12 03:27:42

如果你正在做这个转移很多，你会更好的与std :: vector – 2012-02-12 03:29:36

myRectangle * lastRectanglesArray = new myRectangle[lastMaxLabel]; 
// initialize the entries in the lastRectanglesArray 

// create a temporary array which contains info about each individual 
// entry. namely, it only holds info about whether the entry should 
// be kept, or deleted. 
// we also use the 'entries' value, which is the number of entries 
// in the new array 
bool * entriesToKeep = new bool[lastMaxLabel]; 
int entries = 0; 

// check each entry, and mark whether it should be kept or deleted 
for (int i = 0; i != lastMaxLabel; ++i) { 
    // check whether the entry should be kept or deleted... 
    // here, i just put a function with signature like: 
    // bool shouldKeepRectangle(const myRectangle &); 
    entriesToKeep[i] = shouldKeepRectangle(lastRectanglesArray[i]); 
    if (entriesToKeep[i]) ++entries; 
} 

// create a new array that will contain the entries that should be kept 
myRectangle * rectanglesArray = new myRectangle[entries]; 

// assign the entries in the new array 
for (int i = 0, j = 0; i != lastMaxLabel && j != entries; ++i) { 
    if (entriesToKeep[i]) 
     rectanglesArray[j++] = lastRectanglesArray[i]; 
} 

// free the memory held by the temp array 
delete [] entriesToKeep; 

// if the old array is not needed anymore, delete it 
delete [] lastRectanglesArray; 

// and here you have rectanglesArray, a brand new array that contains 
// only the elements that you need.

来源

2012-02-12 04:09:17 Amy