Border Fox

The code below should take a user entered floating point number and use functions SEPARATE (to break the number up into its individual parts) and PRINTOUT ( to display the individual parts ).
despite my best efforts i seem to be up against a brick wall due to my inexperience.

according to my compiler there are errors on:

num.cpp: In function `int main()':
num.cpp:29: error: syntax error before `(' token
num.cpp: In function `void separate(number)':
num.cpp:37: error: syntax error before `;' token
num.cpp:41: error: non-lvalue in assignment
num.cpp:42: error: non-lvalue in assignment

can anyone help me and sort out these errors? better still, could anyone find a better way of solving the above task because i dont think mine is ever guna work!
I think i needa use FLOOR & FABS in the separate funciton but i dont know how to.


_________________________________________________________________________
1 #include <iostream>
2
3 using std::cout;
4 using std::cin;
5 using std::endl;
6
7 #include <cmath>
8
9 struct number {
10 double initial;
11 char sign;
12 int mag;
13 double fract;
14 };
15
16 void separate ( struct number );
17
18 void printOut ( struct number );
19
20 int main ()
21 {
22 number value;
23
24 cout << "Input a real number (one with decimal point): " << endl;
25 cin >> value.initial;
26
27 separate ( value )
28
29 printOut ( value )
30
31 return 0;
32 }
33
34 void separate ( struct number value )
35 {
36 if ( value.initial > 0 )
37 value.sign = +;
38 else
39 value.sign = -;
40
41 floor ( value.initial ) = value.mag;
42 value.initial - value.mag = value.fract;
43
44 }
45
46 void printOut ( struct number value )
47 {
48 cout << "Number to be analysed: " << value.initial << endl;
49 cout << "Sign: " << value.sign << endl;
50 cout << "Whole number: " << value.mag << endl;
51 cout << "Fractional part: " << value.fract << endl;
52 }

__________________________________________________________________________

drewlander

I can see that there are no semicolons in lines 27 and 29;
if + is to be a char then you need single quotes around them (lines 37 and 39 '+' '-');
and for lines 41 and 42 you have things backwards
floor returns a value, therefore you have to assing value.mag to the leftof it like so:
value.mag=floor ( value.initial );
same with line 42
value.fract = value.initial - value.mag;

doing so made it compile fine for me, hope that helps!

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On and on....

Border Fox

it's stil not working, iv tried implementing these changes and although it compiles error free it gives strange results.
im thinking the functions mustn't be working properly.
can someone help me to get it to compile and run successfully?

Benoit

What errors does the complier give you after correcting the ones he pointed out?

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Border Fox

[d4033875@linux12 ~]$ gcpp ica3.cpp
[d4033875@linux12 ~]$ ica3
Input a real number (one with decimal point):
34.56
Number to be analysed: 34.56
Sign: �
Whole number: 134515518
Fractional part: 1.06444e-304

iv tried debugging methods:

void separate ( struct number value )
{
if ( value.initial > 0 )
value.sign = '+';
else
value.sign = '-';

value.mag = floor ( value.initial );
value.fract = fabs ( value.initial - value.mag );

cout << "In function separate(): " << endl;
cout << "Number to be analysed: " << value.initial << endl;
cout << "Sign: " << value.sign << endl;
cout << "Whole number: " << value.mag << endl;
cout << "Fractional part: " << value.fract << endl << endl;

}

and also

cout << "Input a real number (one with decimal point): " << endl;
cin >> value.initial;

separate ( value );

cout << "After function separate(): " << endl;
cout << "Number to be analysed: " << value.initial << endl;
cout << "Sign: " << value.sign << endl;
cout << "Whole number: " << value.mag << endl;
cout << "Fractional part: " << value.fract << endl << endl;


printOut ( value );


this enabled me to see that the problem lies in main ( i think )
when i did the debuggin in function separate the program successfully compiled error-free, it printed the correct results...BUT it also printed a second set of incorrect results after the correct set. see below:

[d4033875@linux12 ~]$ gcpp ica3.cpp
[d4033875@linux12 ~]$ ica3
Input a real number (one with decimal point):
23.45
In function separate():
Number to be analysed: 23.45
Sign: +
Whole number: 23
Fractional part: 0.45

Number to be analysed: 23.45
Sign: �
Whole number: 134515794
Fractional part: 1.06444e-304


from this i think that function separate is fine.
but the values arent being passed back to main....OR ELSE the values aren't being passed from main to printOut....OR ELSE there is something wrong with printOut.


question is.,...what? and how do i fix it? HELP!!

Monster

You are (almost) correct. The values are not passed correctly to the separate function.

That's because you are passing the complete struct. What the program will do is create a copy of the struct and put it on the stack. The separate function will modify the copy of the struct, not the original struct.

To solve this you need to pass the address of the struct. The separate function can use this address to access (and modify) the struct.

Something like this:

Border Fox

i have posted this problem on 3 separate forums....sorry monster but u have been beaten to the solution.
another guy give me 2 solutions, the one im using is the one you gave which is perfect.
thanx anyway.

i have another minor problem in another program....this one should take two user entered dates (as structures) and determine whether or not they are the same.
my program works but it needs a bit of validating ( even tho i dont think we get marked on validation but it just tidies the program up)

here's the code:

-----------------------------------------------------------------------------------------------------------------------------------

#include <iostream>

using std::cout;
using std::cin;
using std::endl;

struct date {
int day;
char month [ 10 ];
int year;
};

int isequal ( struct date, struct date );

int main ()
{
struct date date1;
struct date date2;

cout << "\n";
cout << "Input the day for date1: " << endl;
cin >> date1.day;
cout << "Input the month for date1 (as a 3-lettered abbreviation eg: jan, feb, mar ): " << endl;
cin >> date1.month;
cout << "Input the year for date1: " << endl;
cin >> date1.year;
cout << "\n";
cout << date1.day << '/' << date1.month << '/' << date1.year << endl;

cout << "\n";
cout << "Input the day for date2: " << endl;
cin >> date2.day;
cout << "Input the month for date2 (as a 3-lettered abbreviation eg: jan, feb, mar ): " << endl;
cin >> date2.month;
cout << "Input the year for date2: " << endl;
cin >> date2.year;
cout << "\n";
cout << date2.day << '/' << date2.month << '/' << date2.year << endl;

cout << "\n";
if ( isequal ( date1, date2 ) == 0 )
cout << "The two dates are exactly the same" << endl;
else
cout << "The two dates are not the same" << endl;
cout << "\n";

return 0;
}

int isequal ( struct date date1, struct date date2 )
{
if ( date1.day == date2.day && date1.year == date2.year &&
!strcmp ( date1.month, date2.month ) )
return 0;
else
return 1;
}

-------------------------------------------------------------------------------------------------------------------------------

here's part of script file:

[d4033875@linux12 ~]$ gcpp ica2.cpp
[d4033875@linux12 ~]$ ica2

Input the day for date1:
12
Input the month for date1 (as a 3-lettered abbreviation eg: jan, feb, mar ):
01
Input the year for date1:
2000

12/01/2000

Input the day for date2:
13
Input the month for date2 (as a 3-lettered abbreviation eg: jan, feb, mar ):
05
Input the year for date2:
1954

13/05/1954

The two dates are not the same



As you can see the program works but there is no limits....people could enter February 31st, or make up months of their own.
the main problem is that if i entered for example 31/12/2000 as date1, and 31/dec/2000 as date 2...they dont match.
or 14/january/2000 and 14/jan/2000 dont match etc etc etc.

i tried countering this by prompting users to enter months with a 3 letter abbreviation of the month name. however this doesnt stop them making up months or using numbers or whatever.
i think when i compare the strings i should compare each element of the array in the string. that way i could compare 'jan' to 'january' and see they are the same....right?

anybody know how to do this ( or some kind of method that would work???)

Hockeyman

Instead of allowing users to input months as text strings, why not enforce a numeric entry for the month? That way you'd only have to test to make sure the number is between 1 and 12 to validate...
If you want to allow users to enter either text or numbers, I'd first check to see which they entered. If they enter a number, see above. If they entered text, convert that to the numeric equivilant (use a switch perhaps?) and then compare.
Sorry no code - trying to get this in while at work...

__________________

codetaino

I agree with hockeyman, but if you still want to use the abreviation... why dont you validate it when they enter the info and ask for it again... if they entered it incorrectly?? you can use a loop to do this

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Border Fox

because i have to use the structure as shown, integer day, month as a string, year as an integer.