第25行应为不合格的-id，我该如何更正

错误出现在第25行括号处。程序读取、计数和平均文件数据文件中的值。我不知道它可能是什么，我已经检查了代码中的分号和所有内容。不过它不会编译。

#include <iostream>
    #include <fstream>
    using namespace std;
    void  ReadAndSum(ifstream&, int&, float&); // Reads, counts, and averages the values on file dataFile.
    int main()
    {
        ifstream  dataFile;
        int  numberOfValues;
        float  average;
        cout << fixed << showpoint;
        dataFile.open("Averages.txt");
        ReadAndSum(dataFile, numberOfValues,average);
        cout << "The average of " << numberOfValues << " values is " << average  << endl;
        return 0;
    }
    void ReadAndSum(ifstream& dataFile, int& numberOfValues, float& average);
    {
        float number;
        numberOfValues = 0;
        average=0;
        dataFile >> number;
        while (dataFile)
        {
            average = average + number;
            numberOfValues++;
            dataFile>>number;
        }
        average = average/numberOfValues;
    }