Compile error Message [duplicate]

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Boolean and Void problem

So I have this code that has a sum function that sums n elements in a vector

C++ Syntax (Toggle Plain Text)

#include <iostream>
#include <vector> // need this in order to use vectors in the program
using namespace std;


void computeSum (vector<int> &Vec, int howMany, int total, bool success)
    //the computeSum function that will sum positive numbers in a vector
{
    int j;
    total=0;
    for(j=0;j < howMany;j++)
        if (Vec[j] > 0){
            total+=Vec[j];
        } else {
            total+=Vec[j+1];
        }
    if (howMany > Vec[j])
        success = false;
    else
        success = true;
    if (total != 0开发者_如何学Go)
        success = true;
    if (success=true){
        cout << total;
    } else {
        cout << "Oops! Appears you cannot add up these numbers!";
    }

}

int main()
{
    vector<int> dataVec;
    bool success;
    int i, n, howMany, total;
    cout << "How many numbers would you like to put into the vector? \n";
    cin >> n;

    dataVec.resize(n);

    for(vector<int>::size_type i=0;i < n;i++)
    {
        cout << "Enter your number for " << i+1 << ": \n";
        cin >> dataVec[i];
    }

    cout << "How many POSITIVE numbers would you like to sum? \n";
    cin >> howMany;
    cout << "Your total is " << computeSum(dataVec, howMany, total, success);
}

Now before I added the

C++ Syntax (Toggle Plain Text)

bool success;

in the main() - the only error I had was success not declared in main - so now I declared it and I get this...

g++ -I/usr/local/include/bjarne/GUI -I -Wall -O3 -DNDEBUG -Wno-deprecated proj1.cc -o proj1
proj1.cc: In function ‘int main()’:
proj1.cc:59:76: error: no match for ‘operator<<’ in ‘std::operator<< [with _Traits = std::char_traits<char>]((* & std::cout), ((const char*)"Your total is ")) << computeSum((* & dataVec), howMany, total, ((int)success))’
proj1.cc:59:76: note: candidates are:
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:110:7: note: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT, _Traits>::__ostream_type& (*)(std::basic_ostream<_CharT, _Traits>::__ostream_type&)) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:110:7: note: no known conversion for argument 1 from ‘void’ to ‘std::basic_ostream<char>::__ostream_type& (*)(std::basic_ostream<char>::__ostream_type&)’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:119:7: note: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT, _Traits>::__ios_type& (*)(std::basic_ostream<_CharT, _Traits>::__ios_type&)) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>, std::basic_ostream<_CharT, _Traits>::__ios_type = std::basic_ios<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:119:7: note: no known conversion for argument 1 from ‘void’ to ‘std::basic_ostream<char>::__ios_type& (*)(std::basic_ostream<char>::__ios_type&)’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:129:7: note: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(std::ios_base& (*)(std::ios_base&)) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:129:7: note: no known conversion for argument 1 from ‘void’ to ‘std::ios_base& (*)(std::ios_base&)’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:167:7: note: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long int) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:167:7: note: no known conversion for argument 1 from ‘void’ to ‘long int’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:171:7: note: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long unsigned int) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:171:7: note: no known conversion for argument 1 from ‘void’ to ‘long unsigned int’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:175:7: note: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(bool) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:175:7: note: no known conversion for argument 1 from ‘void’ to ‘bool’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/bits/ostream.tcc:93:5: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(short int) [with _CharT = char, _Traits = std::char_traits<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/bits/ostream.tcc:93:5: note: no known conversion for argument 1 from ‘void’ to ‘short int’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:182:7: note: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(short unsigned int) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:182:7: note: no known conversion for argument 1 from ‘void’ to ‘short unsigned int’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/bits/ostream.tcc:107:5: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(int) [with _CharT = char, _Traits = std::char_traits<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/bits/ostream.tcc:107:5: note: no known conversion for argument 1 from ‘void’ to ‘int’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:193:7: note: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(unsigned int) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:193:7: note: no known conversion for argument 1 from ‘void’ to ‘unsigned int’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:202:7: note: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long long int) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:202:7: note: no known conversion for argument 1 from ‘void’ to ‘long long int’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:206:7: note: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long long unsigned int) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:206:7: note: no known conversion for argument 1 from ‘void’ to ‘long long unsigned int’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:211:7: note: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(double) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:211:7: note: no known conversion for argument 1 from ‘void’ to ‘double’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:215:7: note: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(float) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:215:7: note: no known conversion for argument 1 from ‘void’ to ‘float’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:223:7: note: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long double) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:223:7: note: no known conversion for argument 1 from ‘void’ to ‘long double’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:227:7: note: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(const void*) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:227:7: note: no known conversion for argument 1 from ‘void’ to ‘const void*’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/bits/ostream.tcc:121:5: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT, _Traits>::__streambuf_type*) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__streambuf_type = std::basic_streambuf<char>]
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/bits/ostream.tcc:121:5: note: no known conversion for argument 1 from ‘void’ to ‘std::basic_ostream<char>::__streambuf_type*’
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/bits/basic_string.h:2694:59: note: template<class _CharT, class _Traits, class _Alloc> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::basic_string<_CharT, _Traits, _Alloc>&)
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:451:65: note: template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, _CharT)
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:456:63: note: template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, char)
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:462:61: note: template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, char)
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:468:68: note: template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, signed char)
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:473:70: note: template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, unsigned char)
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:493:72: note: template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const _CharT*)
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/bits/ostream.tcc:323:70: note: template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const char*)
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:510:5: note: template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, const char*)
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:523:75: note: template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, const signed char*)
/usr/lib/gcc/i686-redhat-linux/4.6.0/../../../../include/c++/4.6.0/ostream:528:77: note: template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, const unsigned char*)
make: *** [proj1] Error 1

....What?

**I even added a return at the end of the int main (( return 0;)) and still am getting the am error

---

You are trying to cout the return value of computeSum which is void. You can't cout << void.

/* computeSum returns void! */
cout << "Your total is " << computeSum(dataVec, howMany, total, success);

---

There are quite a few issues with the program as it turns out. I tried to cover everything, but I may have missed some. And because I blabber on and on it's a bit long.

---

The issue that's giving you the error message is to do with the return type of computeSum(). Right now the return type of computeSum() is void (ie it won't return anything), but in the line where the error occurs you are trying to print whatever is returned by computeSum().

It seems to me like you want 'total' to be returned by computeSum(), not given as a parameter. To do that, instead of making 'total' a parameter declare it at the start of computeSum(), and at the very end of the function add the line

return total;

So computeSum() should look like this:

int computeSum(vector<int> &Vec, int howMany, bool success)
{
    int total = 0;

    //...

    return total;
}

---

There is also a logic error with the adding up part - think what happens when there are two negative numbers in a row for example.

Here is a better version:

int total = 0;
int i = 0;            //the index of the current item being looked at
int numAddedUp = 0;   //the number of positive numbers seen

//loop while need to add up more numbers AND i is within the bounds of Vect
//so stop upon reaching end of Vect even if not added up 'howMany' items yet.
while (numAdded < howMany && i < Vect.size())
{
    if (Vect[i] > 0)
    {
        //if it's positive, add it 
        total += Vect[i];
        numAddedUp++;
    }
    i++;
}

---

The logic of 'success' seems flimsy to me. If you use the while loop I suggested, you can use this instead:

if (numAddedUp == howMany)
{
    success = true;
}
else
{
    success = false;
}

or more briefly,

success = (numAddedUp == howMany);

You could extend the check for detecting special cases such as when howMany is less than one. The following line checks that howMany is valid AND the number of items added up matches howMany:

success = (howMany >= 1) && (numAddedUp == howMany);

Also watch out for the line

if (success=true){

which is assigning (=) the value true to 'success', but what you want to do is check for equality (==).

---

Finally, think about the way you are printing the output. Right now both main() and computeSum() are printing stuff. Ideally, computeSum() wouldn't print anything and the total would be returned along with a bool indicating success/failure. However, a much easier (but not good practice) approach would be to have computeSum() print the output and not even bother returning anything. The main() method would simply have to call the function like this:

computeSum(dataVec, howMany);

as the output will be printed in computeSum() along with nice, detailed, user-friendly error messages such as "The program is not working. Live with it." or "You broke the program!".