目录搜索
AlgorithmsAlgorithms(算法)bsearchbsearch_sqsortqsort_sAtomic operationsAtomic operations library(原子操作库)ATOMIC_*_LOCK_FREEatomic_compare_exchange_strongatomic_compare_exchange_strong_explicitatomic_compare_exchange_weakatomic_compare_exchange_weak_explicitatomic_exchangeatomic_exchange_explicitatomic_fetch_addatomic_fetch_add_explicitatomic_fetch_andatomic_fetch_and_explicitatomic_fetch_oratomic_fetch_or_explicitatomic_fetch_subatomic_fetch_sub_explicitatomic_fetch_xoratomic_fetch_xor_explicitatomic_flagatomic_flag_clearatomic_flag_clear_explicitATOMIC_FLAG_INITatomic_flag_test_and_setatomic_flag_test_and_set_explicitatomic_initatomic_is_lock_freeatomic_loadatomic_load_explicitatomic_signal_fenceatomic_storeatomic_store_explicitatomic_thread_fence(线程围栏)ATOMIC_VAR_INITkill_dependencymemory_order(内存排序)C keywordsauto(自动存储)break(跳出循环)C keywords(关键词)casecharconst(常量修饰符)continuedefault(预设运算式)dodouble(双精度浮点型)elseenum(枚举类型)extern(全局变量)float(浮点数)forfortrangoto(goto语句)if(if语句)inline(行内函式)intlong(长整型)register(寄存器变量)restrict( restrict类型限定符)returnshortsignedsizeof(sizeof运算符)static(静态变量)struct(结构体)switch(switch语句)typedef(typedef关键字)union(联合体)unsigned(无符号)void(空类型)volatile(volatile变量)while(while语句)_Alignas_Alignof_Atomic_Bool_Complex_Generic_Imaginary_Noreturn_Static_assert_Thread_localC language#define directive#elif directive#else directive#endif directive#error directive#if directive#ifdef directive#ifndef directive#include directive#line directive#pragma directivealignas(对齐指定符)Alternative operators and tokens(替代运算符和令牌)AnalyzabilityArithmetic operatorsArithmetic typesArray declaration(数组声明)Array initialization(阵列初始化)ASCII ChartAssignment operators(赋值运算符)types(atomic类型限定符)Basic conceptsBit fields(位域)break statementC languageC Operator Precedencecast operatorcharacter constant(字符字面量)Comments(注释符)Comparison operators(比较运算符)compound literals(符合字面量)Conditional inclusion(条件包含)Conformance(一致性)const type qualifier(const 限定符)Constant expressions(常量表达)continue statementDeclarations(声明)do-while loopEnumerations(枚举类型)Escape sequences(转义字符)Expressions(表达式)External and tentative definitions(外部和暂定的定义)File scope(文件范围)floating constant(浮点常量)for loopFunction declarations(函数声明)Function definitions(函数声明)FunctionsGeneric selection泛型选择goto statementIdentifier(标示符)if statementImplicit conversions(隐式转换)Increment/decrement operators(前置/后置操作符)Initialization(初始化)inline function specifier(内联函式)integer constantLifetime(生命期)Logical operators(逻辑运算符)Lookup and name spacesMain function(主函式)Member access operators(会员接入运营商)Memory modelObjects and alignment(字节对齐)Order of evaluation(评估顺序)Other operatorsPhases of translation(翻译阶段)Pointer declarationPreprocessor(预处理)restrict type qualifier(restrict类型限定符)return statementScalar initialization(标量类型初始化)Scope(范围)sizeof operator(sizeof运算符)Statements(陈述)static assert declaration(静态断言声明)Static storage duration(静态存储周期)Storage-class specifiers(存储类说明符)string literals(字符串字面量)Struct and union initialization(结构体与联合体初始化)Struct declaration(结构体声明)switch statementThread storage duration(线程存储时间)TypeType(类型)Typedef declaration(Typedef声明)Undefined behavior(未定义行为)Union declaration(联合体声明)Value categories(值类别)Variadic arguments(变长参数宏)volatile type qualifier(volatile 类型限定符)while loop_Alignof operator_Noreturn function specifierDate and timeasctime(asctime函数)asctime_sclockCLOCKS_PER_SECclock_tctime(ctime函数)ctime_sDate and time utilities(日期和时间库)difftime(计算两个时间的间隔)gmtimegmtime_slocaltimelocaltime_smktime(将时间结构数据转换成经过的秒数的函数)strftime(格式化输出时间函数)timetimespectimespec_gettime_ttmwcsftime(格式化时间宽字符)Dynamic memory managementaligned_allocC memory management library(内存管理库)callocfree(释放动态分配空间的函数)malloc(动态分配内存空间的函数)realloc(重新分配内存空间的函数)Error handlingabort_handler_sassert(断言)constraint_handler_terrno(错误报告)Error handling(错误处理)Error numbers(错误个数)ignore_handler_sset_constraint_handler_sstatic_assertFile input/outputclearerr(清除/复位)fclosefeofferrorfflush(清空文件缓冲区)fgetcfgetposfgetsfgetwcfgetwsFile input/outputfopenfopen_sfprintffprintf_sfputcfputsfputwcfputwsfreadfreopenfreopen_sfscanffscanf_sfseekfsetposftellfwidefwprintffwprintf_sfwritefwscanffwscanf_sgetcgetchargetsgets_sgetwcharperrorprintfprintf_sputcputcharputsputwcputwcharremoverenamerewindscanfscanf_ssetbufsetvbufsnprintfsprintfsscanfsscanf_sswprintfswprintf_sswscanfswscanf_stmpfiletmpfile_stmpnamtmpnam_sungetcungetwcvfprintfvfprintf_svfscanfvfscanf_svfwprintfvfwprintf_svfwscanfvfwscanf_svprintfvprintf_svscanfvscanf_svsnprintfvsprintfvsscanfvsscanf_svswprintfvswprintf_svswscanfvswscanf_svwprintfvwprintf_svwscanfvwscanf_swprintfwprintf_swscanfwscanf_sLocalization supportlconvLC_ALLLC_COLLATELC_CTYPELC_MONETARYLC_NUMERICLC_TIMElocaleconvLocalization supportsetlocaleNumericsabsacosacosfacoshacoshfacoshlacoslasinasinfasinhasinhfasinhlasinlatanatan2atan2fatan2latanfatanhatanhfatanhlatanlcabscabsfcabslcacoscacosfcacoshcacoshfcacoshlcacoslcargcargfcarglcasincasinfcasinhcasinhfcasinhlcasinlcatancatanfcatanhcatanhfcatanhlcatanlcbrtcbrtfcbrtlccosccosfccoshccoshfccoshlccoslceilceilfceillcexpcexpfcexplcimagcimagfcimaglclogclogfcloglCMPLXCMPLXFCMPLXLCommon mathematical functionscomplexComplex number arithmeticconjconjfconjlcopysigncopysignfcopysignlcoscosfcoshcoshfcoshlcoslcpowcpowfcpowlcprojcprojfcprojlcrealcrealfcreallcsincsinfcsinhcsinhfcsinhlcsinlcsqrtcsqrtfcsqrtlctanctanfctanhctanhfctanhlctanldivdouble_terferfcerfcferfclerfferflexpexp2exp2fexp2lexpfexplexpm1expm1fexpm1lfabsfabsffabslfdimfeclearexceptfegetenvfegetexceptflagfegetroundfeholdexceptferaiseexceptfesetenvfesetexceptflagfesetroundfetestexceptfeupdateenvFE_ALL_EXCEPTFE_DFL_ENVFE_DIVBYZEROFE_DOWNWARDFE_INEXACTFE_INVALIDFE_OVERFLOWFE_TONEARESTFE_TOWARDZEROFE_UNDERFLOWFE_UPWARDFloating-point environmentfloat_tfloorfloorffloorlfmafmaffmalfmaxfmaxffmaxlfminfminffminlfmodfmodffmodlfpclassifyFP_INFINITEFP_NANFP_NORMALFP_SUBNORMALFP_ZEROfrexpfrexpffrexplHUGE_VALHUGE_VALFHUGE_VALLhypothypotfhypotlIilogbilogbfilogblimaginaryimaxabsimaxdivINFINITYisfiniteisgreaterisgreaterequalisinfislessislessequalislessgreaterisnanisnormalisunorderedlabsldexpldexpfldexplldivlgammalgammaflgammalllabslldivllrintllrintfllrintlllroundllroundfllroundlloglog10log10flog10llog1plog1pflog1pllog2log2flog2llogblogbflogbllogflogllrintlrintflrintllroundlroundflroundlMATH_ERREXCEPTmath_errhandlingMATH_ERRNOmodfmodffmodflnanNANnanfnanlnearbyintnearbyintfnearbyintlnextafternextafterfnextafterlnexttowardnexttowardfnexttowardlNumericspowpowfpowlPseudo-random number generationrandRAND_MAXremainderremainderfremainderlremquoremquofremquolrintrintfrintlroundroundfroundlscalblnscalblnfscalblnlscalbnscalbnfscalbnlsignbitsinsinfsinhsinhfsinhlsinlsqrtsqrtfsqrtlsrandtantanftanhtanhftanhltanltgammatgammaftgammaltrunctruncftrunclType-generic math_Complex_I_Imaginary_IProgram supportabortatexitat_quick_exitexitEXIT_FAILUREEXIT_SUCCESSgetenvgetenv_sjmp_buflongjmpProgram support utilitiesquick_exitraisesetjmpSIGABRTSIGFPESIGILLSIGINTsignalSIGSEGVSIGTERMsig_atomic_tSIG_DFLSIG_ERRSIG_IGNsystem_ExitStringsatofatoiatolatollbtowcc16rtombc32rtombchar16_tchar32_tisalnumisalphaisblankiscntrlisdigitisgraphislowerisprintispunctisspaceisupperiswalnumiswalphaiswblankiswcntrliswctypeiswdigitiswgraphiswloweriswprintiswpunctiswspaceiswupperiswxdigitisxdigitmblenmbrlenmbrtoc16mbrtoc32mbrtowcmbsinitmbsrtowcsmbsrtowcs_smbstate_tmbstowcsmbstowcs_smbtowcmemchrmemcmpmemcpymemcpy_smemmovememmove_smemsetmemset_sNull-terminated byte stringsNull-terminated multibyte stringsNull-terminated wide stringsstrcatstrcat_sstrchrstrcmpstrcollstrcpystrcpy_sstrcspnstrerrorstrerrorlen_sstrerror_sStrings librarystrlenstrncatThread supportcall_oncecnd_broadcastcnd_destroycnd_initcnd_signalcnd_timedwaitcnd_waitmtx_destroymtx_initmtx_lockmtx_plainmtx_recursivemtx_timedmtx_timedlockmtx_trylockmtx_unlockonce_flagONCE_FLAG_INITthrd_busythrd_createthrd_currentthrd_detachthrd_equalthrd_errorthrd_exitthrd_jointhrd_nomemthrd_sleepthrd_successthrd_timedoutthrd_yieldThread support librarythread_localtss_createtss_deleteTSS_DTOR_ITERATIONStss_gettss_setType supportBoolean type support libraryFixed width integer typesFLT_EVAL_METHODFLT_ROUNDSmax_align_tNULLNumeric limitsoffsetofptrdiff_tsize_tType supportVariadic functionsVariadic functionsva_argva_copyva_endva_listva_start
文字

在头文件<math.h>中定义



float       crealf( float complex z );

(1)

(since C99)

double      creal( double complex z );

(2)

(since C99)

long double creall( long double complex z );

(3)

(since C99)

Defined in header <tgmath.h>



#define creal( z )

(4)

(since C99)

1-3)返回实数部分z

4)式泛型宏:如果z具有类型long double complexlong double imaginarylong doublecreall被调用。如果z有类型float complexfloat imaginary或者floatcrealf被调用。如果z有类型double complexdouble imaginarydouble,或任何整数类型,creal被调用。

参数

z

-

复杂的论点

返回值

真实的部分z

该函数完全为所有可能的输入指定,并且不受math_errhandling中描述的任何错误的影响。

笔记

对于任何复杂的变量zz == creal(z) + I*cimag(z)

#include <stdio.h>#include <complex.h>
 int main(void){    
    double complex z = 1.0 + 2.0*I;    printf("%f%+fi\n", creal(z), cimag(z));}

输出:

1.000000+2.000000i

参考

  • C11标准(ISO / IEC 9899:2011):

    • 7.3.9.6 creal函数(p:198-199)

    • 7.25类型通用数学<tgmath.h>(p:373-375)

    • G.7类型 - 通用数学<tgmath.h>(p:545)

  • C99标准(ISO / IEC 9899:1999):

    • 7.3.9.5 creal函数(p:180)

    • 7.22类型通用数学<tgmath.h>(p:335-337)

    • G.7类型 - 通用数学<tgmath.h>(p:480)

上一篇:下一篇: