C++ Partial Sorting Errors - c++

Question

What I wanted to do is generate n numbers of nearly sorted value.
For example, user will enter nvalue of 1000.
It will then pass the sorting job by calling the partial sorting function.
Basically, I will just sort half of the total values.
Meaning to say, out of 1000 that has been generated..only first half or 500 values will be sorted only.
After done sorting, it shall push all the nearly sorted value into a vector.
However, I was facing some errors which I can't understand what does it mean during compilation. Can anyone help me on these? Thank you
2 following errors:
1)'partial_sort' : ambiguous call to overloaded function c:\users\mk\documents\visual studio 2013\projects\algorithm analysis\algorithm analysis\nearlysorted.cpp 49 1 Algorithm Analysis
2)IntelliSense: more than one instance of overloaded function "partial_sort" matches the argument list:
function template "void partial_sort(rand_access begin, rand_access sort, rand_access end)"
function template "void std::partial_sort(_RanIt _First, _RanIt _Mid, _RanIt _Last)"
argument types are: (std::_Vector_iterator>>, std::_Vector_iterator>>, std::_Vector_iterator>>) c:\Users\Mk\Documents\Visual Studio 2013\Projects\Algorithm Analysis\Algorithm Analysis\nearlysorted.cpp 49 2 Algorithm Analysis
Code:
#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
template <class rand_access>//class
void partial_sort(
rand_access begin,
rand_access sort,
rand_access end
);
template <class rand_access, class BinaryPred>//overloading
void partial_sort(
rand_access begin,
rand_access sort,
rand_access end,
BinaryPred comp
);
//Function prototype
//void decrease_store(int val, vector<int> &aVec); TODO SOON
void nearlystd_store(int val, vector<int> &aVec);
int main()
{
int nvalue;
vector<int> int_vector;
cout << "How many numbers would you like to generate?\n";
cin >> nvalue;//get input from user
nearlystd_store(nvalue, int_vector);// pass user input to the function
system("pause");
return 0;
}
void nearlystd_store(int val, vector<int> &aVec)//nearly sorted function
{
vector<int>::iterator Iter;// a vector
int num;
for (int i = 0; i < val; i ++)//generate from the start till desired nvalue
{
aVec.push_back(val - i);//push into this vector
}
partial_sort(aVec.begin(), aVec.begin() + (val / 2), aVec.end());//sort half in the vector
cout << "The Output:\n";
for (Iter = aVec.begin(); Iter != aVec.end(); ++Iter)//push sorted value
{
cout << *Iter << " " << endl;//aVec.push_back(int()); --- Not sure if correct
}
}
EDITTED CODE:
Thanks to both llya & Chris for helping out
#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
//Function prototype
//void decrease_store(int val, vector<int> &aVec); TODO SOON
void nearlystd_store(int val, vector<int> &aVec);
int main()
{
int nvalue;
vector<int> int_vector;
cout << "How many numbers would you like to generate?\n";
cin >> nvalue;//get input from user
nearlystd_store(nvalue, int_vector);// pass user input to the function
system("pause");
return 0;
}
void nearlystd_store(int val, vector<int> &aVec)//nearly sorted function
{
vector<int>::iterator Iter;// a vector
for (int i = 0; i < val; i ++)//generate from the start till desired nvalue
{
aVec.push_back(val - i);//push into this vector
}
partial_sort(aVec.begin(), aVec.begin() + (val / 2), aVec.end());//sort half in the vector
cout << "The Output:\n";
for (Iter = aVec.begin(); Iter != aVec.end(); ++Iter)//push sorted value
{
cout << *Iter << " " << endl;//aVec.push_back(int()); --- Not sure if correct
}
}

Answer 1

Let's see compilation errors (next time add it in a question!):
prog.cpp: In function ‘void nearlystd_store(int, std::vector<int>&)’:
prog.cpp:49:68: error: call of overloaded ‘partial_sort(std::vector<int>::iterator, __gnu_cxx::__normal_iterator<int*, std::vector<int> >, std::vector<int>::iterator)’ is ambiguous
partial_sort(aVec.begin(), aVec.begin() + (val / 2), aVec.end());//sort half in the vector
^
prog.cpp:49:68: note: candidates are:
prog.cpp:8:6: note: void partial_sort(rand_access, rand_access, rand_access) [with rand_access = __gnu_cxx::__normal_iterator<int*, std::vector<int> >]
void partial_sort(
^
In file included from /usr/include/c++/4.8/algorithm:62:0,
from prog.cpp:3:
/usr/include/c++/4.8/bits/stl_algo.h:5308:5: note: void std::partial_sort(_RAIter, _RAIter, _RAIter) [with _RAIter = __gnu_cxx::__normal_iterator<int*, std::vector<int> >]
partial_sort(_RandomAccessIterator __first,
^
Here compiler informs your, that it is hard to decide, which implementation of partial_sort must be called. There are two possible options, so compiler can't be sure, which one is right. You need to avoid such uncertainty. In this case you can rename wrong declaration (i.e. remove all lines from 'template //class' to '//Function prototype').
prog.cpp:43:9: warning: unused variable ‘num’ [-Wunused-variable]
int num;
^
And this is just warning. Here you declared variable num, but never use it. It is better to remove such lines from a code to simplify it.