Solving C Programming Issues: Read & Calculate Numbers

[tandoorichicken]

For a homework assignment I need to be able to read in a string of numbers and display them on the screen, and then use them in some calculations. How would be the best way to go about this?
Here's what I have so far to give you an idea of what I need to do:

int n;
double a[15];
printf("Here is the problem:\n");
printf("Enter the number of elements (<16): ");
scanf("%d", n);
printf("\nEnter %d double f-p numbers:\n", n);

Next the user enters 'n' float-point numbers on the screen, and I need to somehow scan that into a[]. How would I do this?

 

[Leo32]

Best way of approaching programming issues is to approach them from a programming language independent viewpoint.

Imagine you have a person who can handle only one simple instruction at a time, how would you instruct this person to do the job ?

Write this out.

Only when finished think about the data you need to store and the specific programming approach. If you do this, it will be much clearer exactly where the problem is, and somebody will be able to hint you further.

Regards,
Leo

 

[tandoorichicken]

Okay, I think I might have that problem figured out. However, here is part of another program I am having trouble with. Could somebody please check the code to make sure nothing is wrong. The compiler doesn't catch anything, so I know it's probably a logic or common sense error on my part.

#include <stdio.h>
#include <math.h>
void problem(void);
double g_value(double x);

void main(void) {
problem(void);
}

void problem (void) {
double x, g_x;
printf("Here is the problem:\n");
printf("Enter a double f-p number:");
scanf("%lf", x);
g_x = g_value(x);
printf("g(%f) = %e", x, g_x);
return;
}

double g_value(double x) {
double g;
if (x>=3.0) g = x*x*x - x*x - 9.0*x + 9;
if (-4.0<x<3.0) g = x*cos(x);
if (x<=-4.0) g = x + 3;
return g;
}

The program runs down to about "Enter a double f-p number" and then abruptly ends with something called a "Segmentation Fault (core dump)."
Can anyone shed some light on this?