How to solve a polynomial given "x" in C.

[Bruce Gregory]

I am 17 and trying to learn C, so I bought "Programming in C" by Stephan Kochan. I have made it to the 4th chapter on the 6th exercise and I cannot get this simple question:

Write a program to evaluate the polynomial shown here:
3x^3 - 5x^2 + 6
for x = 2.55

I did this:

//Polynomial Solver

#include <stdio.h>

int main(void)
{
    double x = 2.55;
    double answer = 3 * (x * x) - 5 * (x * x) + 6;

    printf ("3x^3 - 5x^2 + 6 = %d\n", answer);

    return 0;
}

but it will not give me the correct answer.


I know this is really basic, but please help!

Thanks

[stahta01]

double answer = 3 * (x * x) - 5 * (x * x) + 6;

How many x are there bold above?
How many should there be?

Tim S.

[Bruce Gregory]

double answer = 3 * (x * x) - 5 * (x * x) + 6;

How many x are there bold above?
How many should there be?

Tim S.

I see what you mean, but when I run it, it does run, I get this error in codeblocks:
Process terminated with status -1073741510 (0 minutes, 5 seconds)

[stahta01]

%d means integer
%f means float/double in printf

Turn your warnings on when your compile!

H:\SourceCode\Projects\TestProjects\testc\main.c|8|warning: format '%d' expects argument of type 'int', but argument 2 has type 'double' [-Wformat]|

Tim S.