c++ - main.obj : error LNK2019: unresolved externa

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What is an undefined reference/unresolved external symbol error and how do I fix it?

(34个答案)

5年前关闭。

我知道这个特殊错误已经被提出了十二次了，但是通过我的所有搜索，我一直没有找到与我的具体情况相关的解决方案。

我是一名从Java学习C++的大学生。我知道使用 vector 而不是数组会更好。我也知道我可能理解错误的指针，希望您的解释能在这方面为我提供帮助。

好的，这是我的三个文件:

main.cpp

#include <iostream>
#include "Arrays.h"

// Global variables
const int ARRAY_SIZE = 4;
const int MIN_RANGE = 0;
const int MAX_RANGE = 100;

// Main function
int main()
{
    // Create two arrays populated with random numbers
    int* Array1 = createArray(ARRAY_SIZE, MIN_RANGE, MAX_RANGE); // One of these days I'll understand why ponters are so cool
    int* Array2 = createArray(ARRAY_SIZE, MIN_RANGE, MAX_RANGE); // Right now I find them a tad irritating

    // Create the third array
    int* Array3 = mergeArrays(Array1, Array2);

    // Print all arrays with the format "array1[1] + array2[1] = array3[1]"
    for (size_t i = 0; i < ARRAY_SIZE; i++)
    {
        std::cout << Array1[i] << " + " << Array2[i] << " = " << Array3[i] << std::endl << std::endl;
    }

    // Wait for input...
    system("pause");

    return 0;
}

数组

// Fucntion Prototypes
int* createArray(int arraySize, int minRange, int maxRange); // Creates an array populated with random numbers
int* mergeArrays(int* firstArray, int* secondArray); // Creates an array by adding the associated eements of two arrays
void printHeader(); // Prints the program's header

Arrays.cpp

#include <cstdlib>
#include <ctime>
#include "Arrays.h"

// Function to create an array with n random numbers between 0 and x
int* createArray(int arraySize, int minRange, int maxRange)
{
    srand(time(NULL)); // Generate seed for rand()

    int* Array = new int[arraySize]; // Create a pointer to a new array

    for (size_t i = 0; i < arraySize; i++) // Loop to assign values to each index in the array
    {
        // Generate a random number for each index in the array
        Array[i] = (rand() % maxRange) + minRange;
    }

    return Array;
}

// Function to create an array from two arrays with the associated values added together
int* mergeArrays(int* firstArray, int* secondArray, int arraySize)
{
    int* resultArray = new int[arraySize]; // Create a pointer to a new array

    for (size_t i = 0; i < arraySize; i++) // Loop to assign values to each index in the array
    {
        /* The value at each index in the array is equal to the sum of the values
        at the same index in the other two arrays*/
        resultArray[i] = firstArray[i] + secondArray[i];
    }

    return resultArray;
}

在Visual Studio 2013中构建该错误时，出现的错误是:

1>main.obj : error LNK2019: unresolved external symbol "int * __cdecl mergeArrays(int *,int *)" (?mergeArrays@@YAPAHPAH0@Z) referenced in function _main
1>C:\Assignment 2_1\Debug\Assignment 2_1.exe : fatal error LNK1120: 1 unresolved externals

最佳答案

声明和实现之间有区别。

int* mergeArrays(int* firstArray, int* secondArray) //.h
int* mergeArrays(int* firstArray, int* secondArray, int arraySize) //.cpp

您的主要功能使用.h文件中的功能，但是，此功能从未实现。
在cpp文件中，您声明一个具有相同名称但另一个签名(重载)的函数

关于c++ - main.obj : error LNK2019: unresolved external symbol in C++ [duplicate]，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/28709673/