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Join Date: Jan 2009

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titosd

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func return 2 values

Jan 10th, 2009

Hello,

I have a question, How I can write a function that return 2 values.
the function should take 3 numbers and do between the first and the second number an arethmetic operation and check if the result will be the third number, if yes the function return 1 and return the character of the arethmetic operation.
for example: the function take the numbers 3 5 15, the function will check the three numbers, and will fint that 3*5= 15, so it will return 1 and return *.

I hope that you understand me, and I hope that you can help me with the first thread

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Join Date: Aug 2008

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grumpier

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Re: func return 2 values

Jan 10th, 2009

A common way of return multiple values is by returning a struct which has multiple members, or for the function to accept a pointer that receives additional data from the function.

You don't actually need to return multiple values though: return 0 if there is no operation, '*' if multiplication is the operation, '+' if addition, etc etc. '*', '+', '-', and '/' are non-zero characters with all character sets that I know of.

Last edited by grumpier; Jan 10th, 2009 at 6:10 am.

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titosd

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Re: func return 2 values

Jan 10th, 2009

thank you grampier
but by the question that i have I should reurn 2 values if there is operation return 1 and the character, I asked somebody the all tell me that I should use the pointers but anyone of them know how should write the function.

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minas1

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Re: func return 2 values

Jan 10th, 2009

You can't return two values from a functio using the return statement. Use a struct as you've been told to above:

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
typedef struct
{
int x, y;
} P;
 
P getPoint()
{
int a, b;
//a = .... b = .....
P temp;
temp.x = a;
temp.y = b;
return temp;
}
typedef struct
{
int x, y;
} P;

P getPoint()
{
int a, b;
//a = .... b = .....
P temp;
temp.x = a;
temp.y = b;
return temp;
}

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Join Date: Jan 2009

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titosd

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Re: func return 2 values

Jan 10th, 2009

thanks minas
but I want use the poiner, I sure that I can use the pointer, but I didn't know how to use it !!

is anyone know ?

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Join Date: Aug 2008

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grumpier

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Re: func return 2 values

Jan 10th, 2009

You need to put some effort into understanding the answers you receive, rather than giving up if you're not given code examples.

The approach with using pointers is;

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
SomeTypeA Function( <arguments>,   SomeTypeB *x)
{
       *x = whatever_data_needed_other_than_return_value();
       return return_value();
}
SomeTypeA Function( <arguments>,   SomeTypeB *x)
{
       *x = whatever_data_needed_other_than_return_value();
       return return_value();
}

The "SomeTypeB *x" argument is what I was referring to when I said "or the function to accept a pointer that receives additional data from the function".

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Join Date: Nov 2008

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minas1

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Re: func return 2 values

Jan 10th, 2009

So 1 has to be returned for you to know that the result is the third number. You can do it with only one return value:

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
char arithmeticOperation(int a, int b, int c)
{
	// +
	if(a + b == c) return '+';
 
	// -
	if(a - b == c) return '-';
 
	//you also do this if the order you pass the numbers isn't critical
	if(b - a == c) return '-';
 
	// *
	if(a * b == c) return '*';
 
	// /
	if(a / b == c) return '/';
	if(b / a == c) return '/';
 
	// %
	if(a % b == c) return '%';
	if(b % a == c) return '%';
 
	//if nothing matches
	return ' '; // return a space
}
 
int main(void)
{
	char c = arithmeticOperation(4, 2, 0);
 
	if(c == ' ') // check if it's a space which means there isn't an operation
		printf("No arithmetic operation found.\n");
	else
		printf(%c, "Operation ", c, " found.\n");
}
char arithmeticOperation(int a, int b, int c)
{
	// +
	if(a + b == c) return '+';

	// -
	if(a - b == c) return '-';

	//you also do this if the order you pass the numbers isn't critical
	if(b - a == c) return '-';

	// *
	if(a * b == c) return '*';

	// /
	if(a / b == c) return '/';
	if(b / a == c) return '/';

	// %
	if(a % b == c) return '%';
	if(b % a == c) return '%';

	//if nothing matches
	return ' '; // return a space
}

int main(void)
{
	char c = arithmeticOperation(4, 2, 0);

	if(c == ' ') // check if it's a space which means there isn't an operation
		printf("No arithmetic operation found.\n");
	else
		printf(%c, "Operation ", c, " found.\n");
}

Last edited by minas1; Jan 10th, 2009 at 7:12 am.

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titosd

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Re: func return 2 values

Jan 10th, 2009

thank you grumpier
but I didn't understand the example, if you can give me actual example plz.

minas thank you, but I said that we should write the function with pointers, and te function should return 2 values (the character and the number 1).

I can write it by the structer but we should write it just with pointers !!!