Problem with function call

[bluetxxth]

Hi there,

I am trying to make a program to convert currency.

I am stuck in a function call, more specifically this one part below. Instead of getting the the amount of euros I get for exchanging USD, I get a very long number which does not make sense. As I don't get any warning or error and all compiles fine I don't know what I am doing wrong... Can anyone help? / thnx, Bluetxxth.

#include <stdio.h>
#include <stdlib.h>
#define RATE 1.3 // the exchange rate


/*Function takes input from the user (USD and it converts them to EUR
 * Param: doble - usd integer which holds the ammount of USD
 * Return: double - change in Euros
 */

double usd_to_eur(double usd) {

    double rate = 1 / RATE; // euro conversion rate
    double change;

    printf("Enter currency in USD: ");
    scanf("%f", &usd);

    change = usd * rate;

    return change;
}

int main(void) {

    double chng, // variable which contains the return value of the function usd_to_eur()
            eur; //variable for the actual parameter int the function call which corresponds to the formal parameter

    chng = usd_to_eur(eur);
    printf("Exchange is: %.2f", chng); // prints the result of the currency conversion


    return (0);
}

[rags_to_riches]

Compiling with errors on:

eur.c:17: warning: format ‘%f’ expects type ‘float *’, but argument 2 has type ‘double *’

[bluetxxth]

Hi there,

Thank much !! ... I am using Net Beans on a Windows environment and I don't see that warning when I compile...

br,

Gabriel

[nonoob]

It doesn't make sense to be passing eur to the function usd_to_eur() since it's never assigned. Within the function it is used as a local variable usd which is fine... but it didn't need to be passed as a parameter.

[bluetxxth]

Hi and thank you all for the help.

I have taken notice of the two suggestions I have received. and that part of the program is working fine now.

[rags_to_riches]

C uses pass-by-value when passing parameters to functions. You need to use pass-by-reference.

[bluetxxth]

Hi there,

Thank you for your answer... I guess you mean I need a pointer.. .if so I was suspecting this....

BR,

Bluetxxth