Code compiles fine, but won't build (netbeans IDE)/function issues

Chris Thrower

I am just learning to code and am having an issue with a function. Here is the code, and I'll explain below...

#include <stdio.h>
#include <stdlib.h>

void calc(float a, float b);

int main(void)
{
    float x;
    float y;
    printf("This program will calculate ((X-Y)/X*Y\n");


    printf("Enter X and Y: ");

    while(scanf("%f %f", &x, &y) == 2)
    {
        calc(x,y);   //HERE IS THE ISSUE THE IDE IS POINTING TO
         printf("\nEnter X and Y: ");
    }

    void calc(float a, float b)
    {
        float answer = (a-b)/a*b;
        printf("Answer: %f", answer);
    }

}

The issue is with the calc() function, error message during the program build is...
relocation truncated to fit: r_x86_64_pc32 against undefined symbol calc();

What the heck am I doing wrong? It compiles just fine, but I don't understand this problem.