ctoa.go

     1  // Copyright 2020 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package strconv
     6  
     7  // FormatComplex converts the complex number c to a string of the
     8  // form (a+bi) where a and b are the real and imaginary parts,
     9  // formatted according to the format fmt and precision prec.
    10  //
    11  // The format fmt and precision prec have the same meaning as in FormatFloat.
    12  // It rounds the result assuming that the original was obtained from a complex
    13  // value of bitSize bits, which must be 64 for complex64 and 128 for complex128.
    14  func FormatComplex(c complex128, fmt byte, prec, bitSize int) string {
    15  	if bitSize != 64 && bitSize != 128 {
    16  		panic("invalid bitSize")
    17  	}
    18  	bitSize >>= 1 // complex64 uses float32 internally
    19  
    20  	// Check if imaginary part has a sign. If not, add one.
    21  	im := FormatFloat(imag(c), fmt, prec, bitSize)
    22  	if im[0] != '+' && im[0] != '-' {
    23  		im = "+" + im
    24  	}
    25  
    26  	return "(" + FormatFloat(real(c), fmt, prec, bitSize) + im + "i)"
    27  }
    28
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