-lm

#include <stdio.h>
#include <tgmath.h>
typedef double complex point_t;
static inline double sq_norm(point_t p) { return p * conj(p); }
int main(void) {
  printf("Keyin x and y values >> ");
  fflush(stdout);
  double x, y;
  if (scanf("%lf%lf", &x, &y) == 2) {
    point_t p = CMPLX(x, y);
    printf("%.1f\n", sq_norm(p));
  }
}