Get rid of compiling warning?

Code:

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#include <stdio.h>
double fiveycost(double house, double fuel_cost, double tax_rate);
int main()
{
        printf("This program determines the total cost of owning a home for five years.\nThe user will enter initial cost in whole dollars, annual fuel costs in whole dollars, and the annual tax rate as a real number.\n");


        printf("Please enter the initial cost, fuel cost, and tax rate: ");
        double house;
        double fuel_cost;
        double tax_rate;
        scanf("%lf %lf %lf", &house,&fuel_cost,&tax_rate);
  (Line 13) printf(" The total cost is $%lf.",fiveycost);
        return 0;
}


        double fiveycost( double house, double fuel_cost, double tax_rate)
        {
                double taxes=(house*tax_rate);
                return (5.0*taxes)+(house)+(5.0*fuel_cost)

}

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The error is on line 13
:Warning: format '%lf' expects argument of type 'double', but argument 2 has type 'double (*)(double, double, double)' [-Wformat]

Not so sure why its showing an error. I mean i changed integer 5 to 5.0.
I declared everything as double.

You never passed your function any arguments... double fiveycost( double house, double fuel_cost, double tax_rate); look at your prototype some more. You must pass it 3 doubles.

Quote:

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Originally Posted by tmac619619

:Warning: format '%lf' expects argument of type 'double', but argument 2 has type 'double (*)(double, double, double)' [-Wformat]

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That type, 'double (*)(double, double, double)', is a function pointer type. This is because the effect of this line:

Code:

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printf(" The total cost is $%lf.",fiveycost);

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is not to call the fiveycost function. You need to pass arguments to fiveycost. Function calls look like

Code:

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func() //no args
func2(a, b) // 2 args

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Using "fiveycost" on its own like this means the type is that of a function pointer, and the value is an address. You don't need to worry about the details of that bit right now.

Could you help me out with passing arguments?

I'm not sure what it would look like

You just pass what you want into your function... In your case it would look like

Code:

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printf("%lf",fiveycost(house, fuel_cost, tax_rate));

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Notice that you drop the key words "Double" with each variable passed.

Thanks it worked.

Code:

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printf(" The total cost is $%lf.",fiveycost);

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Code:

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printf("The total cost is%lf",fiveycost(house, fuel_cost, tax_rate));

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What is the difference between those two?
The first one doesn't work because i just presented the function fiveycost, but haven't called any arguments right?

Yes, here is a link that should help you clear up some concepts on functions.
Functions in C - Cprogramming.com

Thank you.

Once i learn this, i will never forget it.