求教!我初学 关于容器的简单操作的错误

#include <iostream>
#include <vector>
using namespace std;

void test1(vector<int>& myv)
{
if(myv.size() % 2 = 0)
{
cout << "even element" << endl;
for(vector<int>::size_type index = 0;index < myv.size() - 1;++index)
cout << myv[index] + myv[index + 1] << endl;
}
else
{
cout << "odd nember element" << endl;
for(vector<int>::size_type index = 0;index < myv.size() - 2;++index)
cout << myv[index] + myv[index + 1] << endl;
cout << myv[index + 2] << "is lefted" << endl;
}
}

int main()
{
vector<int> myv;

for(vector<int>::size_type index = 0;index < 10;++index)
myv.push_back(index);

text1(m

#include <iostream>
#include <vector>
using namespace std;

void test1(vector<int>& myv);

int main()
{
vector<int> myv;
for(vector<int>::size_type index = 0;index < 10;++index)
myv.push_back(index);
test1(myv);
system("pause");
return 0;
}

void test1(vector<int>& myv)
{
if(myv.size() % 2 ==0)
{
cout << "even element" << endl;
for(vector<int>::size_type index = 0;index < myv.size() - 1;++index)
cout << myv[index] + myv[index + 1] << endl;
} //end if
else
{
cout << "odd nember element" << endl;
vector<int>::size_type index = 0;
for(index;index < myv.size() - 2;++index)
cout << myv[index] + myv[index + 1] << endl;
cout << myv[index + 2] << "is lefted" << endl;
}
}