Trunc - C++ Reference

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Reference

• C library:

  • <cassert> (assert.h)
  • <cctype> (ctype.h)
  • <cerrno> (errno.h)
  • C++11 <cfenv> (fenv.h)
  • <cfloat> (float.h)
  • C++11 <cinttypes> (inttypes.h)
  • <ciso646> (iso646.h)
  • <climits> (limits.h)
  • <clocale> (locale.h)
  • <cmath> (math.h)
  • <csetjmp> (setjmp.h)
  • <csignal> (signal.h)
  • <cstdarg> (stdarg.h)
  • C++11 <cstdbool> (stdbool.h)
  • <cstddef> (stddef.h)
  • C++11 <cstdint> (stdint.h)
  • <cstdio> (stdio.h)
  • <cstdlib> (stdlib.h)
  • <cstring> (string.h)
  • C++11 <ctgmath> (tgmath.h)
  • <ctime> (time.h)
  • C++11 <cuchar> (uchar.h)
  • <cwchar> (wchar.h)
  • <cwctype> (wctype.h)

• Containers:

  • C++11 <array>
  • <deque>
  • C++11 <forward_list>
  • <list>
  • <map>
  • <queue>
  • <set>
  • <stack>
  • C++11 <unordered_map>
  • C++11 <unordered_set>
  • <vector>

• Input/Output:

  • <fstream>
  • <iomanip>
  • <ios>
  • <iosfwd>
  • <iostream>
  • <istream>
  • <ostream>
  • <sstream>
  • <streambuf>

• Multi-threading:

  • C++11 <atomic>
  • C++11 <condition_variable>
  • C++11 <future>
  • C++11 <mutex>
  • C++11 <thread>

• Other:

  • <algorithm>
  • <bitset>
  • C++11 <chrono>
  • C++11 <codecvt>
  • <complex>
  • <exception>
  • <functional>
  • C++11 <initializer_list>
  • <iterator>
  • <limits>
  • <locale>
  • <memory>
  • <new>
  • <numeric>
  • C++11 <random>
  • C++11 <ratio>
  • C++11 <regex>
  • <stdexcept>
  • <string>
  • C++11 <system_error>
  • C++11 <tuple>
  • C++11 <type_traits>
  • C++11 <typeindex>
  • <typeinfo>
  • <utility>
  • <valarray>

<cmath> (math.h)

• functions

  • abs
  • acos
  • C++11 acosh
  • asin
  • C++11 asinh
  • atan
  • atan2
  • C++11 atanh
  • C++11 cbrt
  • ceil
  • C++11 copysign
  • cos
  • cosh
  • C++11 erf
  • C++11 erfc
  • exp
  • C++11 exp2
  • C++11 expm1
  • fabs
  • C++11 fdim
  • floor
  • C++11 fma
  • C++11 fmax
  • C++11 fmin
  • fmod
  • C++11 fpclassify
  • frexp
  • C++11 hypot
  • C++11 ilogb
  • C++11 isfinite
  • C++11 isgreater
  • C++11 isgreaterequal
  • C++11 isinf
  • C++11 isless
  • C++11 islessequal
  • C++11 islessgreater
  • C++11 isnan
  • C++11 isnormal
  • C++11 isunordered
  • ldexp
  • C++11 lgamma
  • C++11 llrint
  • C++11 llround
  • log
  • log10
  • C++11 log1p
  • C++11 log2
  • C++11 logb
  • C++11 lrint
  • C++11 lround
  • modf
  • C++11 nan
  • C++11 nanf
  • C++11 nanl
  • C++11 nearbyint
  • C++11 nextafter
  • C++11 nexttoward
  • pow
  • C++11 remainder
  • C++11 remquo
  • C++11 rint
  • C++11 round
  • C++11 scalbln
  • C++11 scalbn
  • C++11 signbit
  • sin
  • sinh
  • sqrt
  • tan
  • tanh
  • C++11 tgamma
  • C++11 trunc

• macro constants

  • HUGE_VAL
  • C++11 HUGE_VALF
  • C++11 HUGE_VALL
  • C++11 INFINITY
  • C++11 math_errhandling
  • NAN

• types

  • C++11 double_t
  • float_t

• Reference
• <cmath>
• trunc

function <cmath> <ctgmath> trunc double trunc ( double x); float truncf ( float x);long double truncl (long double x); double trunc ( double x); float trunc ( float x);long double trunc (long double x); double trunc (T x); // additional overloads for integral types Truncate value Rounds x toward zero, returning the nearest integral value that is not larger in magnitude than x. Header <tgmath.h> provides a type-generic macro version of this function. Additional overloads are provided in this header (<cmath>) for the integral types: These overloads effectively cast x to a double before calculations (defined for T being any integral type).

Parameters

x Value to truncate.

Return Value

The nearest integral value that is not larger in magnitude than x (as a floating-point value).

Example

1234567891011121314151617

/* round vs floor vs ceil vs trunc */ #include <stdio.h> /* printf */ #include <math.h> /* round, floor, ceil, trunc */ int main () { const char * format = "%.1f \t%.1f \t%.1f \t%.1f \t%.1f\n"; printf ("value\tround\tfloor\tceil\ttrunc\n"); printf ("-----\t-----\t-----\t----\t-----\n"); printf (format, 2.3,round( 2.3),floor( 2.3),ceil( 2.3),trunc( 2.3)); printf (format, 3.8,round( 3.8),floor( 3.8),ceil( 3.8),trunc( 3.8)); printf (format, 5.5,round( 5.5),floor( 5.5),ceil( 5.5),trunc( 5.5)); printf (format,-2.3,round(-2.3),floor(-2.3),ceil(-2.3),trunc(-2.3)); printf (format,-3.8,round(-3.8),floor(-3.8),ceil(-3.8),trunc(-3.8)); printf (format,-5.5,round(-5.5),floor(-5.5),ceil(-5.5),trunc(-5.5)); return 0; }

Output:

value round floor ceil trunc ----- ----- ----- ---- ----- 2.3 2.0 2.0 3.0 2.0 3.8 4.0 3.0 4.0 3.0 5.5 6.0 5.0 6.0 5.0 -2.3 -2.0 -3.0 -2.0 -2.0 -3.8 -4.0 -4.0 -3.0 -3.0 -5.5 -6.0 -6.0 -5.0 -5.0

See also

floorRound down value (function)ceilRound up value (function)roundRound to nearest (function)rintRound to integral value (function) Home page | Privacy policy© cplusplus.com, 2000-2025 - All rights reserved - v3.3.4s Spotted an error? contact us