Program keeps printing 0

[purplehaze]

#include <stdio.h>


int main ()  {

int amount;

scanf("Enter in an amount in dollars %d\n", &amount);

amount = amount + amount *.05;
printf("Your total amount is %d\n", amount);


return 0;


}

This is pretty embarrassing, but i cant fix this logic error, any hints? Thanks.

[tabstop]

Do you notice how your "prompt" isn't printed to the screen? And are you typing in exactly

Enter in an amount in dollars 55

at that lack-of-prompt?

[Adak]

Which is to say, you need to print your prompt message to the user, and THEN have your scanf() line of code.

This is NOT BASIC (which does it that way).

Multiplying an integer by .05 will not do anything you like. There are two ways to deal with this:

1) use a float or a double data type for the money, but not ALL values can be represented by these data types.

2) Get the money in as a string, and then remove the decimal point if it has one. Then transfer it over to your money variable as an int, but it will be in pennies - not dollars.

Which sounds weird, but it's actually perfect - integers are perfect for pennies because you never have fractions of a penny, in real life.

[claudiu]

Also, for optimum results don't do floating point arithmetic and store results in an integer.

[purplehaze]

Thanks Adask, that helped a lot. @claudiu, wouldnt there be a precision error in the final answer if i do it this way?

[claudiu]

Thanks Adask, that helped a lot. @claudiu, wouldnt there be a precision error in the final answer if i do it this way?

If you want a floating point number then why not just make your variable a double and use the %lf flag instead of %d?

[purplehaze]

If you want a floating point number then why not just make your variable a double and use the %lf flag instead of %d?

Ah, ok. You see, from the C book im reading i was under the impression that a variable declared as float x ; for example was a double and that the way to make a variable a float is to use the "f" keyword such as float x = 4.0f. Anyhow, i'll remember the %lf, thanks.

[claudiu]

Ah, ok. You see, from the C book im reading i was under the impression that a variable declared as float x ; for example was a double and that the way to make a variable a float is to use the "f" keyword such as float x = 4.0f. Anyhow, i'll remember the %lf, thanks.

Floats are also floating point variables. You can use a float if you want to, that's fine, I just usually avoid them and prefer to use doubles instead. Indeed the flag for float is %f