检查在数组c ++中是否找到元素 [英] Check if element found in array c++

问题描述

如何检查我的数组是否有我正在寻找的元素？

在Java中，我会这样做：

  Foo someObject = new Foo（someParameter）; 
 Foo foo; 
 //搜索Foo [] arr 
 for（int i = 0; i  if arr [i] .equals（someObject）
 foo = arr [i]; 
} 
 if（foo == null）
 System.out.println（Not found！）; 
 else 
 System.out.println（Found！）; 
  

但是在C ++中我不认为我可以搜索一个Object是否为空在C ++中，你将使用 std :: find $ c>，并检查结果指针是否指向范围的结尾，如下所示：

  Foo array [10] ; 
 ... //在这里初始化数组
 Foo * foo = std :: find（std :: begin（array），std :: end（array），someObject）; 
 //当没有找到元素时，std :: find返回范围的结束
 if（foo！= std :: end（array））{
 cerr< Found at position<< std :: distance（array，foo）<< endl; 
} else {
 cerr<< 未找到<< endl; 
} 
  




How can I check if my array has an element I'm looking for?

In Java, I would do something like this:

Foo someObject = new Foo(someParameter);
Foo foo;
//search through Foo[] arr
for(int i = 0; i < arr.length; i++){
  if arr[i].equals(someObject)
    foo = arr[i];
}
if (foo == null)
  System.out.println("Not found!");
else
  System.out.println("Found!");

But in C++ I don't think I'm allowed to search if an Object is null so what would be the C++ solution?

解决方案

In C++ you would use std::find, and check if the resultant pointer points to the end of the range, like this:

Foo array[10];
... // Init the array here
Foo *foo = std::find(std::begin(array), std::end(array), someObject);
// When the element is not found, std::find returns the end of the range
if (foo != std::end(array)) {
    cerr << "Found at position " << std::distance(array, foo) << endl;
} else {
    cerr << "Not found" << endl;
}

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