链接错误:多个定义 [英] Linking Error: Multiple definitions
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问题描述
我正在尝试编译我的项目，并得到函数错误的多个定义:
I'm trying to compile my project and getting multiple definition of function error:
CMakeFiles/OasisTest.dir/Tests/Oasis_test.cpp.o: In function `MinHeap::left(int)':
/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/Tests/../DataStructures/MinHeap.h:56: multiple definition of `MinHeap::MinHeap(int)'
CMakeFiles/OasisTest.dir/Oasis.cpp.o:/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/DataStructures/MinHeap.h:56: first defined here
似乎我的头文件中有变量定义，应该删除或将其定义为 extern ，或将其定义为 inline ，但我不知道该更改什么.
It seems that I have variable definitions in my header file, and those should be removed or made extern, or made inline,
but I don't have an idea what to change.
注意:我成功地在没有 MinHeap.h
我要在 CMakeLists.txt 中进行编译的内容:
What I'm trying to compile as in CMakeLists.txt:
add_executable(OasisTest
Oasis.cpp
Tests/Oasis_test.cpp
)
MinHeap.h
#ifndef OASIS_MINHEAP_H
#define OASIS_MINHEAP_H
#include <iostream>
#include <climits>
using namespace std;
// Prototype of a utility function to swap two integers
void swap(int* x, int* y);
// A class for Min Heap
class MinHeap {
int* harr; // pointer to array of elements in heap
int capacity; // maximum possible size of min heap
int heap_size; // Current number of elements in min heap
public:
// Constructor
MinHeap(int cap);
// to heapify a subtree with the root at given index
void MinHeapify(int);
int parent(int i) { return (i - 1) / 2; }
// to get index of left child of node at index i
int left(int i) { return (2 * i + 1); }
// to get index of right child of node at index i
int right(int i) { return (2 * i + 2); }
// to extract the root which is the minimum element
int extractMin();
// Decreases key value of key at index i to new_val
void decreaseKey(int i, int new_val);
// Returns the minimum key (key at root) from min heap
int getMin() { return harr[0]; }
// Deletes a key stored at index i
void deleteKey(int i);
// Inserts a new key 'k'
void insert(int k);
bool isEmpty();
};
// Constructor: Builds a heap from a given array a[] of given size
MinHeap::MinHeap(int cap) {
heap_size = 0;
capacity = cap;
harr = new int[cap];
}
// Inserts a new key 'k'
void MinHeap::insert(int k) {
if (heap_size == capacity) {
cout << "\nOverflow: Could not insert\n";
return;
}
// First insert the new key at the end
heap_size++;
int i = heap_size - 1;
harr[i] = k;
// Fix the min heap property if it is violated
while (i != 0 && harr[parent(i)] > harr[i]) {
swap(&harr[i], &harr[parent(i)]);
i = parent(i);
}
}
// Decreases value of key at index 'i' to new_val. It is assumed that
// new_val is smaller than harr[i].
void MinHeap::decreaseKey(int i, int new_val) {
harr[i] = new_val;
while (i != 0 && harr[parent(i)] > harr[i]) {
swap(&harr[i], &harr[parent(i)]);
i = parent(i);
}
}
// Method to remove minimum element (or root) from min heap
int MinHeap::extractMin() {
if (heap_size <= 0)
return INT_MAX;
if (heap_size == 1) {
heap_size--;
return harr[0];
}
// Store the minimum value, and remove it from heap
int root = harr[0];
harr[0] = harr[heap_size - 1];
heap_size--;
MinHeapify(0);
return root;
}
// This function deletes key at index i. It first reduced value to minus
// infinite, then calls extractMin()
void MinHeap::deleteKey(int i) {
decreaseKey(i, INT_MIN);
extractMin();
}
// A recursive method to heapify a subtree with the root at given index
// This method assumes that the subtrees are already heapified
void MinHeap::MinHeapify(int i) {
int l = left(i);
int r = right(i);
int smallest = i;
if (l < heap_size && harr[l] < harr[i])
smallest = l;
if (r < heap_size && harr[r] < harr[smallest])
smallest = r;
if (smallest != i) {
swap(&harr[i], &harr[smallest]);
MinHeapify(smallest);
}
}
bool MinHeap::isEmpty() {
return heap_size <= 0;
}
// A utility function to swap two elements
void swap(int* x, int* y) {
int temp = *x;
*x = *y;
*y = temp;
}
#endif //OASIS_MINHEAP_H
包括 Oasis.h
#include "library2.h" //Only typedefs
#include "DataStructures/HashTable.h" //Includes AVLTree.h
#include "DataStructures/AVLRankTree.h" //Include to AvlExceptions
#include "DataStructures/MinHeap.h"
Oasis.cpp
#include "Oasis.h"
Oasis_test.cpp
#include "TestMacros.h"
#include "../Oasis.h"
完整错误:
CMakeFiles/OasisTest.dir/Tests/Oasis_test.cpp.o: In function `MinHeap::left(int)':
/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/Tests/../DataStructures/MinHeap.h:56: multiple definition of `MinHeap::MinHeap(int)'
CMakeFiles/OasisTest.dir/Oasis.cpp.o:/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/DataStructures/MinHeap.h:56: first defined here
CMakeFiles/OasisTest.dir/Tests/Oasis_test.cpp.o: In function `MinHeap::left(int)':
/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/Tests/../DataStructures/MinHeap.h:56: multiple definition of `MinHeap::MinHeap(int)'
CMakeFiles/OasisTest.dir/Oasis.cpp.o:/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/DataStructures/MinHeap.h:56: first defined here
CMakeFiles/OasisTest.dir/Tests/Oasis_test.cpp.o: In function `HashTable<int>::destroy_hash()':
/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/Tests/../DataStructures/MinHeap.h:63: multiple definition of `MinHeap::insert(int)'
CMakeFiles/OasisTest.dir/Oasis.cpp.o:/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/DataStructures/MinHeap.h:63: first defined here
CMakeFiles/OasisTest.dir/Tests/Oasis_test.cpp.o: In function `swap(int*, int*)':
/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/Tests/../DataStructures/MinHeap.h:137: multiple definition of `swap(int*, int*)'
CMakeFiles/OasisTest.dir/Oasis.cpp.o:/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/DataStructures/MinHeap.h:137: first defined here
CMakeFiles/OasisTest.dir/Tests/Oasis_test.cpp.o: In function `MinHeap::decreaseKey(int, int)':
/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/Tests/../DataStructures/MinHeap.h:83: multiple definition of `MinHeap::decreaseKey(int, int)'
CMakeFiles/OasisTest.dir/Oasis.cpp.o:/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/DataStructures/MinHeap.h:83: first defined here
CMakeFiles/OasisTest.dir/Tests/Oasis_test.cpp.o: In function `MinHeap::extractMin()':
/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/Tests/../DataStructures/MinHeap.h:92: multiple definition of `MinHeap::extractMin()'
CMakeFiles/OasisTest.dir/Oasis.cpp.o:/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/DataStructures/MinHeap.h:92: first defined here
CMakeFiles/OasisTest.dir/Tests/Oasis_test.cpp.o: In function `MinHeap::MinHeapify(int)':
/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/Tests/../DataStructures/MinHeap.h:118: multiple definition of `MinHeap::MinHeapify(int)'
CMakeFiles/OasisTest.dir/Oasis.cpp.o:/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/DataStructures/MinHeap.h:118: first defined here
CMakeFiles/OasisTest.dir/Tests/Oasis_test.cpp.o: In function `MinHeap::deleteKey(int)':
/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/Tests/../DataStructures/MinHeap.h:111: multiple definition of `MinHeap::deleteKey(int)'
CMakeFiles/OasisTest.dir/Oasis.cpp.o:/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/DataStructures/MinHeap.h:111: first defined here
CMakeFiles/OasisTest.dir/Tests/Oasis_test.cpp.o: In function `MinHeap::isEmpty()':
/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/Tests/../DataStructures/MinHeap.h:132: multiple definition of `MinHeap::isEmpty()'
CMakeFiles/OasisTest.dir/Oasis.cpp.o:/home/d_/CODING/CLionProjects/DS1-Course_Wet2/Oasis-2/DataStructures/MinHeap.h:132: first defined here
推荐答案
您正在定义头文件本身中的每个成员；因此，每当您在源代码中包含头文件时，都会重新定义这些成员；这就是为什么您会收到多个定义错误的原因.要解决此问题，请在类本身中定义每个成员函数，或者将定义从头文件移动到单独的cpp文件(就像其他人建议的一样)，然后将该cpp文件添加到 add_executable 命令中.
You are defining each member in the header file itself; so each time you include the header file in your source code, these members are redefined; that is why you are getting multiple definition error. To resolve this either define each member function in the class itself or move the definitions from header file to a separate cpp file(like other people suggested) and add that cpp file to add_executable command.
这篇关于链接错误:多个定义的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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