Dart Right Shift Assignment

variable >>= shiftAmount;

variable = variable >> shiftAmount;

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Technical Mechanics

• Operand Constraints: Both the left operand (the value being mutated) and the right operand (the shift magnitude) must be of type int.
• Sign Propagation: Dart integers utilize two’s complement binary representation. The >>= operator performs an arithmetic shift, meaning it preserves the most significant bit (the sign bit) during the shift.
  • If the left operand is positive (sign bit 0), empty spaces on the left are filled with 0s.
  • If the left operand is negative (sign bit 1), empty spaces on the left are filled with 1s.
• Truncation: The least significant bits that are shifted past the 0th position on the right are permanently discarded.

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Syntax Visualization

void main() {
  // Positive integer shift
  int a = 24;      // Binary: 0001 1000
  a >>= 2;         // Shift right by 2 bits. Left-fills with 0s.
  print(a);        // Output: 6 (Binary: 0000 0110)

  // Negative integer shift (Sign bit preserved)
  int b = -24;     // Binary: 1110 1000 (Two's complement representation)
  b >>= 2;         // Shift right by 2 bits. Left-fills with 1s.
  print(b);        // Output: -6 (Binary: 1111 1010)
}