what is wrong with my code?

[davy.zou]

I found the code for a program that is suppose to be able to work out
the sumation of i from 1 to a certain integer n.

however, when I implemented to code into Visual C++, it doesn't work.
The original sample code provided by the website:

unsigned int Sum (unsigned int n) {
unsigned int result = 0;
for (unsigned int i=1; i<=n; i++) {
result+=1;
return result;
}
}

and the weblink for this code is http://www.brpreiss.com/books/opus4/html/page37.html

now, I tried to include the whole main function, cin and cout all that
stuff so I can run it and test it. Now the code looks like this:
---------------------------------------------------------------------------------
1#include <iostream.h//assignment number 5087
2
3unsigned int Sum (unsigned int n);
4
5unsigned int Sum (unsigned int n) {
6
7 cout<<"Please enter n: "<<endl;
8 cin>>n;
9
10 unsigned int result = 0;
11 for (unsigned int i=1; i<=n; i++) {
12 result+=1;
13 return result;
14 }
15}
16
17 void main {

a=Sum;
cout<<"Sum is "<<a<<endl;

}
-----------------------------------------------------------
Now the compiler tells me I have got two errors. The error messages
are:
C:\Documents and Settings\Owner\ My Documents\Unive rsity\Data
Structures and Algorithms\samp le 1\Cpp1.cpp(17) : error C2182:
'main' : illegal use of type 'void'

C:\Documents and Settings\Owner\ My Documents\Unive rsity\Data
Structures and Algorithms\samp le 1\Cpp1.cpp(17) : error C2239:
unexpected token '{' following declaration of 'main'.

In other words, there are two things wrong with line 17. one is and
illegal use of type void, which is weird since just about all of my
assignments so far have been done with void main. The other is some
"unexpected token". Somebody help me! I am about the drown in the vast
sea of confusion! :}

[Ian Collins]

da******@brentw ood.bc.ca wrote:

16
17 void main {

a=Sum;
cout<<"Sum is "<<a<<endl;

}
-----------------------------------------------------------
Now the compiler tells me I have got two errors. The error messages
are:
C:\Documents and Settings\Owner\ My Documents\Unive rsity\Data
Structures and Algorithms\samp le 1\Cpp1.cpp(17) : error C2182:
'main' : illegal use of type 'void'

C:\Documents and Settings\Owner\ My Documents\Unive rsity\Data
Structures and Algorithms\samp le 1\Cpp1.cpp(17) : error C2239:
unexpected token '{' following declaration of 'main'.

In other words, there are two things wrong with line 17. one is and
illegal use of type void, which is weird since just about all of my
assignments so far have been done with void main. The other is some
"unexpected token". Somebody help me! I am about the drown in the vast
sea of confusion! :}

Ignoring the rest of the code; main returns int, so void main() is
ill-formed. You are also missing the parenthesis after "main".

--
Ian Collins.

[davy.zou]

>
Ignoring the rest of the code; main returns int, so void main() is
ill-formed. You are also missing the parenthesis after "main".

--
Ian Collins.

LOL. I can't believe it is something that simple. Thank you.

[davy.zou]

What does this mean?

C:\Documents and Settings\Owner\ My Documents\Unive rsity\Data
Structures and Algorithms\samp le 1\Cpp1.cpp(14) : warning C4715:
'Sum' : not all control paths return a value

[Ian Collins]

da******@brentw ood.bc.ca wrote:

What does this mean?

C:\Documents and Settings\Owner\ My Documents\Unive rsity\Data
Structures and Algorithms\samp le 1\Cpp1.cpp(14) : warning C4715:
'Sum' : not all control paths return a value

Please retain some context.

If you look again, you will see that you have your return inside the for
loop. You probably want it outside of the loop.

--
Ian Collins.

[davy.zou]

On May 24, 10:23 pm, Ian Collins <[e-mail] mwrote:

davy....@brentw ood.bc.ca wrote:

What does this mean?

C:\Documents and Settings\Owner\ My Documents\Unive rsity\Data
Structures and Algorithms\samp le 1\Cpp1.cpp(14) : warning C4715:
'Sum' : not all control paths return a value

Please retain some context.

If you look again, you will see that you have your return inside the for
loop. You probably want it outside of the loop.

--
Ian Collins.

how is it that your can reply like right after someone makes a post?
not that I am nor grateful or something, I am very grateful, but do
you like get paid to do this?

[davy.zou]

How do I clear a variable at the end of a while loop?

[Ian Collins]

da******@brentw ood.bc.ca wrote:

On May 24, 10:23 pm, Ian Collins <[e-mail] mwrote:

>davy....@brent wood.bc.ca wrote:

>>What does this mean?
C:\Document s and Settings\Owner\ My Documents\Unive rsity\Data
Structures and Algorithms\samp le 1\Cpp1.cpp(14) : warning C4715:
'Sum' : not all control paths return a value

Please retain some context.

If you look again, you will see that you have your return inside the for
loop. You probably want it outside of the loop.

--
Ian Collins.

Please don't quote people's signatures, the lines after the "-- ".

>
how is it that your can reply like right after someone makes a post?
not that I am nor grateful or something, I am very grateful, but do
you like get paid to do this?

I just happened to be sitting here!

--
Ian Collins.

[Old Wolf]

On May 25, 1:58 pm, davy....@brentw ood.bc.ca wrote:

unsigned int Sum (unsigned int n) {
unsigned int result = 0;
for (unsigned int i=1; i<=n; i++) {
result+=1;
return result;
}
}

and the weblink for this code ishttp://www.brpreiss.co m/books/opus4/html/page37.html

You've made several transcription errors:
* You added extra { }
* You changed "result += i" to "result+=1"
* You changed ++i to i++

The first two drastically change the effect of the code.

1#include <iostream.h//assignment number 5087

(Please don't post line-number listings , it just
makes it harder for us to put your code in our
compilers).

There is no such standard header as <iostream.h.
The C++ standard came out in 1998 so that suggests
your learning materials are 10 years old or more.
You could remedy this by writing:
#include <iostream>
using namespace std;

which has a similar effect to what some old compilers
did when you wrote #include <iostream.h.

3unsigned int Sum (unsigned int n);
4
5unsigned int Sum (unsigned int n) {

Line 3 is redundant (although this isn't a terrible error).

17 void main {

Should be:
int main() {

main must return an int in Standard C++. While there
are some compilers that also allow it to return void,
you may find that your code fails when you try it on
a different compiler.

a=Sum;

Should be:
a = Sum();

You need to use the brackets to indicate that the
function should be called.

[Old Wolf]

On May 25, 4:03 pm, Old Wolf <oldw...@inspir e.net.nzwrote:

On May 25, 1:58 pm, davy....@brentw ood.bc.ca wrote:

unsigned int Sum (unsigned int n) {

a=Sum;

Should be:
a = Sum();

In fact, it should be:
a = Sum(5);

or some other number as an argument to the function.