Newbie question, insertSort algorithm

[MMagique]

Hi guys, I'm trying to compile the following code in Visual Studio 2010 Express for a simple implementation of insertSort:

InsertSort.h
=========

template <class T>
void isort(const T& start, const T& end){

for (T i=start; i<end; ++i){

T::value_type value = *i;
T dec = i;

while(dec>start && *(dec-1) >= value){
*dec = *(dec-1);
--dec;
}

*dec = value;
}
}

ISMain.cpp
========

#include <iostream>
#include "InsertSort.h"
#include <vector>

int main() {

std::vector<double> vec(10, 0.0);
for (int i=0;i<vec.size();i++) {
vec[i] = rand();
}

isort(vec[0], vec[9]);
std::cout << "vector sorted" << std::endl;
return 0;
}

I'm getting a host of error messages:

1>c:\users\hcm\documents\visual studio 2010\projects\insertsort\insertsort\ismain.cpp(3): warning C4067: unexpected tokens following preprocessor directive - expected a newline
1>c:\users\hcm\documents\visual studio 2010\projects\insertsort\insertsort\ismain.cpp(7): error C2039: 'vector' : is not a member of 'std'
1>c:\users\hcm\documents\visual studio 2010\projects\insertsort\insertsort\ismain.cpp(7): error C2065: 'vector' : undeclared identifier
1>c:\users\hcm\documents\visual studio 2010\projects\insertsort\insertsort\ismain.cpp(7): error C2062: type 'double' unexpected
1>c:\users\hcm\documents\visual studio 2010\projects\insertsort\insertsort\ismain.cpp(8): error C2065: 'x' : undeclared identifier
1>c:\users\hcm\documents\visual studio 2010\projects\insertsort\insertsort\ismain.cpp(8): error C2228: left of '.size' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\hcm\documents\visual studio 2010\projects\insertsort\insertsort\ismain.cpp(9): error C2065: 'x' : undeclared identifier
1>c:\users\hcm\documents\visual studio 2010\projects\insertsort\insertsort\ismain.cpp(9): error C2228: left of '.at' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\hcm\documents\visual studio 2010\projects\insertsort\insertsort\ismain.cpp(12): error C2065: 'x' : undeclared identifier
1>c:\users\hcm\documents\visual studio 2010\projects\insertsort\insertsort\ismain.cpp(12): error C2065: 'x' : undeclared identifier
1>c:\users\hcm\documents\visual studio 2010\projects\insertsort\insertsort\ismain.cpp(12): error C3861: 'isort': identifier not found

I'm sure I'm making some obvious mistakes. Any help would be much appreciated!

[Paul McKenzie]

Hi guys, I'm trying to compile the following code in Visual Studio 2010 Express for a simple implementation of insertSort:

Use code tags when posting code.

#include <vector>
template <class T> 
void isort(const T& start, const T& end)
{
   typename T::value_type value = start; // < -- no such thing as double::value_type
}

int main()
{
    std::vector<double> vec(10, 0.0);
    isort(vec[0], vec[9]);  // <--passing doubles here
}

This simple code when compiled shows the issue.

You are passing double to the isort function as the T argument. There is no "value_type" for type double.

Second, you must use the typename keyword as I have shown above for the code to even begin to compile.

Regards,

Paul McKenzie

[MMagique]

Thanks Paul. Your suggestions were very helpful. I now realise that 'T' has to be type iterator and therefore doesn't need to be passed by reference. Code now compiles. Cheers!