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error: expected ',' or ';' before numeric constant — Parallax Forums

error: expected ',' or ';' before numeric constant

I'm new to C programming and I keep getting the error message in the title. I'm following along with the Floating Point Math tutorial and I have compared my statements to the picture but I can't seem to find the problem. It wants me to Expand More Floating Point.c to calculate the volume of a sphere using v = 4/3 × π × r3.
Pre-written Loop:

include "simpletools.h" // Include simpletools

int main()
{
float r = 1.0;
float c = 2.0 * PI * r;
print (“circumference = %f \n”, c);
float a = PI * r * r; // <- add
print(“area =%f \n” , a); // <- add
}
My Loop:

include "simpletools.h" // Include simpletools

int main() // main function
{
float r = 1.0; // Set radius to 1.0
float v = 4.0\3.0 × PI × r^3.0; // Calculate volume
print("volume = %f \n", v); // Display volume
float v = 4.0\3.0 * PI * r * r * r; // <- add
print("volume = %f \n", v); // <- add
}
I'm getting the error for the calculate volume statement.

Comments

  • CJMJCJMJ Posts: 216

    Is the divide operator slanted the correct way? Should it be \ or / ? The compiler may not recognize the \ and thinks you're trying to define a constant like the previous line. Just guessing.

  • iseriesiseries Posts: 1,066

    Here are the corrections.

    float r = 1.0; // Set radius to 1.0
      float v = 4.0/3.0 * PI * pow(r,3); // Calculate volume
      print("volume = %f \n", v); // Display volume
      v = 4.0/3.0 * PI * r * r * r; // <- add
      print("volume = %f \n", v); // <- add
    

    The backslash is not divide.
    The two stars were not stars??? for multiple
    r^3 is not supported.
    once a variable is defined it doesn't need to be defined again.

    Mike

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