Getting user input for structure variables

Hi all,

I am a new programmer so sorry if this is an annoying question. I would very much appreciate your help with the following. I am trying to get a user to input values for a created structure type called car_t. When I input random values the string input works for the newcar.make (it prints exactly what I entered), but whatever I put in for newcar.price it always prints that the value is 0.00000.

Here's my code:

Code:

---

#include <stdio.h>
#include <string.h>

typedef struct {
    double price;
    char make[50];
    }car_t;

int main()
{
    car_t newcar;


    printf("Input make of car: ");


    fgets(newcar.make, 50, stdin);


    printf("\nInput price of car: ");


    scanf("%lf", &newcar.price);


    printf("The make is: %s", newcar.make);


    printf("The price is: $%lf", newcar.price);


    return 0;
}

---

Thanks for your help.

Take the l out of line 29.

Also... unless you are buying a billion dollar car there's no need for a double there... a float would probably be just fine.

Wow... I'm such a fool! So you only need %f for printf() but %lf for scanf()... Thanks so much I feel like an absolute goose.

Quote:

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I feel like an absolute goose.

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You should also turn off your webcam... LOL...

No worries... glad you got it working.

Quote:

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Originally Posted by CommonTater

You should also turn off your webcam... LOL...

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^ I don't get it ha sorry...

I have an extension to this problem.

I want to create a "fleet" of cars - an array of type car_t that can hold up to ten cars. So firstly i'm trying to create an 'addCar' function, that gets input from the user and then returns the structure. I could get it working using a return(*structure*) statement, but i'm trying to do it with passing by reference. Again, my string input gets printed correctly, but it crashes when I try to retrieve the value for the price.

Here's my code:

Code:

---


#include <stdio.h>
#include <string.h>


typedef struct {
    double price;
    char make[50];
    }car_t;


void addCar(car_t *ptrCar);


int main()
{
    car_t newcar;


    addCar(&newcar);


    printf("\nMake of car is %s", newcar.make);


    printf("\nPrice of car is $%.2f", newcar.price);


    return 0;
}


void addCar(car_t *ptrCar)
{
    printf("Input make of car: ");


    fgets(ptrCar->make, 50, stdin);


    printf("\nInput price of car: ");


    scanf("%lf", ptrCar->price);


    return;
}

---

Any ideas? Hopefully it's something stupid again that's easy to fix!

Quote:

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Originally Posted by themolejoel

^ I don't get it ha sorry...

---

You said you felt like a total goose... The humourous infrance was that you look like one too! :D

Quote:

---

I have an extension to this problem.

I want to create a "fleet" of cars - an array of type car_t that can hold up to ten cars. So firstly i'm trying to create an 'addCar' function, that gets input from the user and then returns the structure. I could get it working using a return(*structure*) statement, but i'm trying to do it with passing by reference. Again, my string input gets printed correctly, but it crashes when I try to retrieve the value for the price.

...
Any ideas? Hopefully it's something stupid again that's easy to fix!

---

Not this time... Maybe one of the others can help...

Quote:

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Originally Posted by themolejoel

Any ideas? Hopefully it's something stupid again that's easy to fix!

---

Like CommonTater, I did not find a problem by inspection. However, I compiled your program with compiler warnings turned on, upon which the problem was obvious from the compiler's warning. This:

Code:

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scanf("%lf", ptrCar->price);

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should have been:

Code:

---

scanf("%lf", &ptrCar->price);

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Moral of the story: compile with warnings turned on to a sufficiently high level.

CommonTater and laserlight: Thank you so much for your help! :biggrin: