Member Avatar for railmaster7

I'm making a header file to make, sort, and print a vector using heapsort. I keep getting a compiler error about my const char[100] array. Probably something really simple I'm missing...I hope.

In function `void build_list(std::vector<T, std::allocator<_CharT> >&, const char*)':
16 expected primary-expression before "const"
16 expected `;' before "const"

#ifndef HEAPSORT_H
#define HEAPSORT_H

#include <iostream>
#include <vector>
#include <fstream>
#include <cstring>
#include <iomanip>
#include <algorithm>

using namespace std;

template <class T>
void build_list(vector<T>& itemList, const char* fileName)
{
    const char[100] file = fileName;
    ifstream inFile;
	inFile.open("file");

	if(!inFile)
	{
       cout << "input file did not open";
       cin.get();
       exit(0);
	}
	
	T item;
    while(inFile >> item)
	{
	  itemList.push_back(item);
    }
    
    inFile.close();
}


template <class T>
void print_list(const vector<T>& itemList, int itemWidth, int numPerLine)
{
     int counter = 0;
     //for(int i = itemList.begin(); i != itemList.end(); ++i)
     for(int i = 0; i != itemList.size(); ++i)
     {
        cout << setw(itemWidth) << itemList.at(i);
        if(counter == numPerLine) 
        {
           cout << endl;
           counter = 0;
        }
        counter++;
     }
}
     

template <class T, class Pred>
void sort_list(vector<T>& itemList, Pred predicate)
{
     sort_heap(itemList.begin(), itemList.end());
}

#endif
Edited by railmaster7 because: n/a
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  • Latest Post Latest Post by Dave Sinkula
Member Avatar for Dave Sinkula

I don't think you even want the array, but instead are after this?

inFile.open(file);
Member Avatar for railmaster7

good call. I had one other question. in

template <class T, class Pred>
void sort_list(vector<T>& itemList, Pred predicate)
{
sort_heap(itemList.begin(), itemList.end());
}

I need to use the Pred predicate to determine whether to use the heapsort in ascending or descending order and I'm not sure how to do that.

The description of the argument is : The second argument will be a predicate (a Boolean function) from the STL. This predicate will either be less<T>() (to build a heap that will sort items in ascending order) or greater<T>() (to build a heap that will sort items in descending order).

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