go/src/strconv/ctoa.go

// FormatComplex converts the complex number c to a string of the
// form (a+bi) where a and b are the real and imaginary parts,
// formatted according to the format fmt and precision prec.
//
// The format fmt and precision prec have the same meaning as in [FormatFloat].
// It rounds the result assuming that the original was obtained from a complex
// value of bitSize bits, which must be 64 for complex64 and 128 for complex128.
func FormatComplex(c complex128, fmt byte, prec, bitSize int) string { … }