Question

I am suppose to be creating a memory map of this program for my class, but when I try to compile it, I get an error:

invalid operands to binary expression ('double *' and 'double *')

I am a student, please do not edit the code to print out memory locations, I need to write that myself.

main()
{
double testd;
int testi;
FILE *fpt;

struct frog {
    double *x, y;
}frog;

struct frog turtle, *apple, tv[3];

testi = 2;

apple = &turtle;
apple->x = &testd

*(turtle).x = 7.3;    //this is where im getting the error. 
(*apple).y = 3.6;

turtle.y = 1.5;

for (testi = 0; testi < 3; testi++)
    tv[testi].x = &(tv[(testi+1)%3].y);

*(tv[1].x) = 6.4;
}

Answer 1

You are missing the ; at the end of the previous line.

You are not wrong to dereference *(turtle).x instead of *(turtle.x). The . operator has higher precedence than the * operator, meaning those two statements are equivalent and you don’t even need parentheses: you could just do *turtle.x.

Check out this site for precedence ordering.