Calculating a rectangle

// Online C compiler to run C program online
#include <stdio.h>
#include <math.h>
struct tangle{
    float x,y;
};
struct polar{
    float r, theta;
};

struct polar convert(struct tangle rect){
    struct polar pol;
    if(rect.x==0 && rect.y==0){
        pol.r = pol.theta = 0;
    }
    else{
        pol.r=sqrt(rect.x*rect.x + rect.y*rect.y);
        double ans = (rect.y,rect.x);
        pol.theta = atan(ans);
    }
    return pol;
}

int main() {
    struct tangle rect = {2,1};
    struct polar p;
    p = convert(rect);
    printf("%.2f %.2f",p.r,p.theta);
    
    

    return 0;
}