C complex number and printf
Solution 1:
printf("%f + i%f\n", creal(result), cimag(result));
I don't believe there's a specific format specifier for the C99 complex type.
Solution 2:
Let %+f choose the correct sign for you for imaginary part:
printf("%f%+fi\n", crealf(I), cimagf(I));
Output:
0.000000+1.000000i
Note that i is at the end.