multiple scanf in a program causing crash in c?

Question

#include 

int main()
{       
    printf(\"how old are you? \");
    int age = 0;
    scanf(\"%d\", age);

    printf(\"how much does your daily habit co         


        

Answer 1

scanf("%d", daily);

needs to become

scanf("%d", &daily);

You need to pass the address of the variable (i.e., a pointer, this is done with the &) to scanf so that the value of the variable can be changed. The same applies for your other prompt. Change it to

scanf("%d", &age);

Now you should get this when you run your program:

% a.out
how old are you? 30
how much does your daily habit cost per day? 
20

this year your habit will cost you: 7300.00

Answer 2

scanf works with references to variables

printf("how old are you? ");
int age = 0;
scanf("%d", &age);

printf("how much does your daily habit cost per day? \n");
int daily = 0;
scanf("%d", &daily); 

double thisyear = daily * 365;

printf("\n");
printf("this year your habit will cost you: %.2f", thisyear);

Answer 3

The scanf function expects a pointer.

scanf("%d", &age);

Ditto for the line where you scanf on "daily".