Primitive Type i32 [−]
Operations and constants for signed 32-bits integers (i32 type)
Methods
impl i32
fn min_value() -> Self
Returns the smallest value that can be represented by this integer type.
fn max_value() -> Self
Returns the largest value that can be represented by this integer type.
fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError>
Converts a string slice in a given base to an integer.
Leading and trailing whitespace represent an error.
Examples
fn main() { assert_eq!(u32::from_str_radix("A", 16), Ok(10)); }assert_eq!(u32::from_str_radix("A", 16), Ok(10));
fn count_ones(self) -> u32
Returns the number of ones in the binary representation of self.
Examples
fn main() { let n = 0b01001100u8; assert_eq!(n.count_ones(), 3); }let n = 0b01001100u8; assert_eq!(n.count_ones(), 3);
fn count_zeros(self) -> u32
Returns the number of zeros in the binary representation of self.
Examples
fn main() { let n = 0b01001100u8; assert_eq!(n.count_zeros(), 5); }let n = 0b01001100u8; assert_eq!(n.count_zeros(), 5);
fn leading_zeros(self) -> u32
Returns the number of leading zeros in the binary representation
of self.
Examples
fn main() { let n = 0b0101000u16; assert_eq!(n.leading_zeros(), 10); }let n = 0b0101000u16; assert_eq!(n.leading_zeros(), 10);
fn trailing_zeros(self) -> u32
Returns the number of trailing zeros in the binary representation
of self.
Examples
fn main() { let n = 0b0101000u16; assert_eq!(n.trailing_zeros(), 3); }let n = 0b0101000u16; assert_eq!(n.trailing_zeros(), 3);
fn rotate_left(self, n: u32) -> Self
Shifts the bits to the left by a specified amount, n,
wrapping the truncated bits to the end of the resulting integer.
Examples
fn main() { let n = 0x0123456789ABCDEFu64; let m = 0x3456789ABCDEF012u64; assert_eq!(n.rotate_left(12), m); }let n = 0x0123456789ABCDEFu64; let m = 0x3456789ABCDEF012u64; assert_eq!(n.rotate_left(12), m);
fn rotate_right(self, n: u32) -> Self
Shifts the bits to the right by a specified amount, n,
wrapping the truncated bits to the beginning of the resulting
integer.
Examples
fn main() { let n = 0x0123456789ABCDEFu64; let m = 0xDEF0123456789ABCu64; assert_eq!(n.rotate_right(12), m); }let n = 0x0123456789ABCDEFu64; let m = 0xDEF0123456789ABCu64; assert_eq!(n.rotate_right(12), m);
fn swap_bytes(self) -> Self
Reverses the byte order of the integer.
Examples
fn main() { let n = 0x0123456789ABCDEFu64; let m = 0xEFCDAB8967452301u64; assert_eq!(n.swap_bytes(), m); }let n = 0x0123456789ABCDEFu64; let m = 0xEFCDAB8967452301u64; assert_eq!(n.swap_bytes(), m);
fn from_be(x: Self) -> Self
Converts an integer from big endian to the target's endianness.
On big endian this is a no-op. On little endian the bytes are swapped.
Examples
fn main() { let n = 0x0123456789ABCDEFu64; if cfg!(target_endian = "big") { assert_eq!(u64::from_be(n), n) } else { assert_eq!(u64::from_be(n), n.swap_bytes()) } }let n = 0x0123456789ABCDEFu64; if cfg!(target_endian = "big") { assert_eq!(u64::from_be(n), n) } else { assert_eq!(u64::from_be(n), n.swap_bytes()) }
fn from_le(x: Self) -> Self
Converts an integer from little endian to the target's endianness.
On little endian this is a no-op. On big endian the bytes are swapped.
Examples
fn main() { let n = 0x0123456789ABCDEFu64; if cfg!(target_endian = "little") { assert_eq!(u64::from_le(n), n) } else { assert_eq!(u64::from_le(n), n.swap_bytes()) } }let n = 0x0123456789ABCDEFu64; if cfg!(target_endian = "little") { assert_eq!(u64::from_le(n), n) } else { assert_eq!(u64::from_le(n), n.swap_bytes()) }
fn to_be(self) -> Self
Converts self to big endian from the target's endianness.
On big endian this is a no-op. On little endian the bytes are swapped.
Examples
fn main() { let n = 0x0123456789ABCDEFu64; if cfg!(target_endian = "big") { assert_eq!(n.to_be(), n) } else { assert_eq!(n.to_be(), n.swap_bytes()) } }let n = 0x0123456789ABCDEFu64; if cfg!(target_endian = "big") { assert_eq!(n.to_be(), n) } else { assert_eq!(n.to_be(), n.swap_bytes()) }
fn to_le(self) -> Self
Converts self to little endian from the target's endianness.
On little endian this is a no-op. On big endian the bytes are swapped.
Examples
fn main() { let n = 0x0123456789ABCDEFu64; if cfg!(target_endian = "little") { assert_eq!(n.to_le(), n) } else { assert_eq!(n.to_le(), n.swap_bytes()) } }let n = 0x0123456789ABCDEFu64; if cfg!(target_endian = "little") { assert_eq!(n.to_le(), n) } else { assert_eq!(n.to_le(), n.swap_bytes()) }
fn checked_add(self, other: Self) -> Option<Self>
Checked integer addition. Computes self + other, returning None
if overflow occurred.
Examples
fn main() { assert_eq!(5u16.checked_add(65530), Some(65535)); assert_eq!(6u16.checked_add(65530), None); }assert_eq!(5u16.checked_add(65530), Some(65535)); assert_eq!(6u16.checked_add(65530), None);
fn checked_sub(self, other: Self) -> Option<Self>
Checked integer subtraction. Computes self - other, returning
None if underflow occurred.
Examples
fn main() { assert_eq!((-127i8).checked_sub(1), Some(-128)); assert_eq!((-128i8).checked_sub(1), None); }assert_eq!((-127i8).checked_sub(1), Some(-128)); assert_eq!((-128i8).checked_sub(1), None);
fn checked_mul(self, other: Self) -> Option<Self>
Checked integer multiplication. Computes self * other, returning
None if underflow or overflow occurred.
Examples
fn main() { assert_eq!(5u8.checked_mul(51), Some(255)); assert_eq!(5u8.checked_mul(52), None); }assert_eq!(5u8.checked_mul(51), Some(255)); assert_eq!(5u8.checked_mul(52), None);
fn checked_div(self, v: Self) -> Option<Self>
Checked integer division. Computes self / other, returning None
if other == 0 or the operation results in underflow or overflow.
Examples
fn main() { assert_eq!((-127i8).checked_div(-1), Some(127)); assert_eq!((-128i8).checked_div(-1), None); assert_eq!((1i8).checked_div(0), None); }assert_eq!((-127i8).checked_div(-1), Some(127)); assert_eq!((-128i8).checked_div(-1), None); assert_eq!((1i8).checked_div(0), None);
fn saturating_add(self, other: Self) -> Self
Saturating integer addition. Computes self + other, saturating at
the numeric bounds instead of overflowing.
fn saturating_sub(self, other: Self) -> Self
Saturating integer subtraction. Computes self - other, saturating
at the numeric bounds instead of overflowing.
fn wrapping_add(self, rhs: Self) -> Self
Wrapping (modular) addition. Computes self + other,
wrapping around at the boundary of the type.
fn wrapping_sub(self, rhs: Self) -> Self
Wrapping (modular) subtraction. Computes self - other,
wrapping around at the boundary of the type.
fn wrapping_mul(self, rhs: Self) -> Self
Wrapping (modular) multiplication. Computes self * other, wrapping around at the boundary of the type.
fn wrapping_div(self, rhs: Self) -> Self
Wrapping (modular) division. Computes floor(self / other),
wrapping around at the boundary of the type.
The only case where such wrapping can occur is when one
divides MIN / -1 on a signed type (where MIN is the
negative minimal value for the type); this is equivalent
to -MIN, a positive value that is too large to represent
in the type. In such a case, this function returns MIN
itself..
fn wrapping_rem(self, rhs: Self) -> Self
Wrapping (modular) remainder. Computes self % other,
wrapping around at the boundary of the type.
Such wrap-around never actually occurs mathematically;
implementation artifacts make x % y illegal for MIN / -1 on a signed type illegal (where MIN is the negative
minimal value). In such a case, this function returns 0.
fn wrapping_neg(self) -> Self
Wrapping (modular) negation. Computes -self,
wrapping around at the boundary of the type.
The only case where such wrapping can occur is when one
negates MIN on a signed type (where MIN is the
negative minimal value for the type); this is a positive
value that is too large to represent in the type. In such
a case, this function returns MIN itself.
fn wrapping_shl(self, rhs: u32) -> Self
Panic-free bitwise shift-left; yields self << mask(rhs),
where mask removes any high-order bits of rhs that
would cause the shift to exceed the bitwidth of the type.
fn wrapping_shr(self, rhs: u32) -> Self
Panic-free bitwise shift-left; yields self >> mask(rhs),
where mask removes any high-order bits of rhs that
would cause the shift to exceed the bitwidth of the type.
fn pow(self, exp: u32) -> Self
Raises self to the power of exp, using exponentiation by squaring.
Examples
fn main() { let x: i32 = 2; // or any other integer type assert_eq!(x.pow(4), 16); }let x: i32 = 2; // or any other integer type assert_eq!(x.pow(4), 16);
fn abs(self) -> Self
Computes the absolute value of self.
Overflow behavior
The absolute value of i32::min_value() cannot be represented as an
i32, and attempting to calculate it will cause an overflow. This
means that code in debug mode will trigger a panic on this case and
optimized code will return i32::min_value() without a panic.
fn signum(self) -> Self
Returns a number representing sign of self.
0if the number is zero1if the number is positive-1if the number is negative
fn is_positive(self) -> bool
Returns true if self is positive and false if the number
is zero or negative.
fn is_negative(self) -> bool
Returns true if self is negative and false if the number
is zero or positive.