#include <stdio.h>
 
#include <complex.h>
#define M y*=1.5-n*y*y/2
i;_Complex float f(float m){float y,n;n=m>0?m:-m;y=n;i=0x5f3759df-*(int*)&y/2;y=*(float*)&i;M;M;M;return m>0?y*n:y*n*I;}
 
 
int main (int argc, char **argv) {
    int i;
    _Complex float result;
    float testcases[] = { 0, 4, 7, 5.0625, -15, -9 };
 
    for (i = 0; i < sizeof(testcases) / sizeof(testcases[0]); i++) {
      result = f(testcases[i]);
      printf("%f + %fi\n", creal(result), cimag(result));
    }
 
    return 0;
}
 

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