Problem with structure function

**gell10** · 06-06-2004

hi, it's me again. This time I am having problems writing a function that alters the data of the structure type. this is what i have can anyone tell me why it doesn't work. Thanks

Code:

#include <iostream.h>
#include <string>

using namespace std;

struct individualtype ///////includes monsters and characters
{
	string mainname;
	string name;
	int level;
	float maxhp;
	float hp;
	float maxmp;
	float mp;
	float luck;
	float vitality;
	float strength;
	float accuracy;
	float speed;
	float defense;
	float blackmagic;
	float whitemagic;
	float greenmagic;
	float skillpoints;
}; 

individualtype adventurer;
individualtype monster;

int setpoints(int level, individualtype x)
{
	//if level one
	x.maxhp=10;
	x.maxmp=6;
	x.luck=2;
	x.vitality=2;
	x.strength=7;
	x.accuracy=5;
	x.speed=5;
	x.defense=7;
	x.blackmagic=2;
	x.whitemagic=2;
	x.greenmagic=2;
	x.skillpoints=0;
	////if past level one
	for(int b=1;b<x.level;b++)
	{
		x.maxhp=x.maxhp*3/2;
		x.maxmp=x.maxmp*4/3;
		x.luck=x.luck*5/4;
		x.vitality=x.vitality*5/4;
		x.strength=x.strength*9/7;
		x.accuracy=x.accuracy*6/5;
		x.speed=x.speed*6/5;
		x.defense=x.defense*9/7;
		x.blackmagic=x.blackmagic*5/4;
		x.whitemagic=x.whitemagic*5/4;
		x.greenmagic=x.greenmagic*5/4;
	}	
	return 0;
}

int main();
{
          adventurer.level=1;
          monster.level=1;
          cout<<"Hello"<<endl;
          setpoints(adventurer.level, adventurer);
          setpoints(monster.level, monster);
          cout<<monster.maxhp<<endl;
          return 0;
}

all the values remain 0 they do not change when i try to display them. I think it should work, someone please correct my reasoning I think i may be off.

**vasanth** · 06-06-2004

[QUOTE=gell10]

Code:

for(int b=1;b<x.level;b++)
 
 
int main();
{
adventurer.level=1;
monster.level=1;
setpoints(adventurer.level, adventurer);
setpoints(monster.level, monster);

I see that you are initilising adventurer.level and monster.level to 1 in the for lopp you are using the value of x.level to control the loop.. when it is 1 the loop will not run since the condion is b=1;b<1;b++ .. It will not run because b is not less than 1....

to make this work use

[QUOTE]

Code:

for(int b=1;b<=x.level;b++)

or

Code:

for(int b=0;b<x.level;b++)

**electRONix** · 06-06-2004

couple pointers..
int main(); ... semicolon =d u probably caught that yourself... and instead of doing something like
x=x*3/2;
u can do this
x*=3/2;
...
and in addition to help debug your program... try just changing one attribute and then checking to see if was changed... in other words, start small, make sure it works, and then add on...
For example, you might want to start with a simpler structure that has just has strength and level, and then see if you can increase strength according to the level.

if you still have problems email me. your code looks easy enough to debug i can work on it with you. i'd take a closer look now but its almost 2 am and im gettin a lil tired =d

**gell10** · 06-06-2004

hehe ok but my problem is i want to be able to alter the data in my structures through a generic function
for example (this is code i am making up right now so bear with me) =)

Code:

#include <iostream.h>

int businessnumbergenerator(business x);

struct business
{
        float income;
        float expenses;
};

business mcdonalds;
business dennys;

int main()
{
        cout<<"check businesses"<<endl;
        businessnumbergenerator(mcdonalds);
        businessnumbergenerator(dennys);
        return 0;
}

int businessnumbergenerator(business x);
{
        x.income=50;
        x.expenses=34;
        return 0;
}

**gell10** · 06-06-2004

i guess my question is, is that code possible because it doesn't seem to work for me

**laserlight** · 06-06-2004

Are you doing this for a hobby?

It might be easier to manage this using classes in an objected oriented model instead.

**gell10** · 06-06-2004

yeah i'm a beginner, i'm trying to learn about functions and stuff before i move onto graphics. is there a way to perform the function i said above or would i have to type out each structure individually? am i making sense? do i have to use classes instead?

**anonytmouse** · 06-06-2004

Currently, you are passing the structure by value. This means that a copy of the structure is passed to the function. Changes made to the copy will not be reflected in the original.

You need to pass the structure by reference. This means that a reference to the original is passed to the function instead of a copy.

Code:

int main()
{
        cout<<"check businesses"<<endl;
        businessnumbergenerator(mcdonalds);
        businessnumbergenerator(dennys);
        return 0;
}

// The & specifies that the argument should be passed by reference
int businessnumbergenerator(business & x);
{
        x.income=50;
        x.expenses=34;
        return 0;
}

Alternatively, you can pass a pointer to the original.

Code:

int main()
{
        cout<<"check businesses"<<endl;
        // Pass the address of each structure to the function
        businessnumbergenerator(&mcdonalds);
        businessnumbergenerator(&dennys);
        return 0;
}

// The asterisk signifies that this function takes a pointer to a business structure
int businessnumbergenerator(business * x);
{
        // We use the -> operator instead of . This dereferences the structure
        // pointer and accesses the specified member.
        x->income=50;
        x->expenses=34;
        return 0;
}

**gell10** · 06-06-2004

Thank you that works wonderfully :-D

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