g++ a.cpp a.cpp: In function 'int main(int, char**)': a.cpp:20:17: error: 'isnumber' was not declared in this scope if (isnumber(i)) { ^ 我也用clang3.8.1来测试: clang++ a.cpp --std=c++11 a.cpp:20:7: error: use of undeclared identifier 'isnumber' if (isnumber(i)) ...
The isdigit() function in C++ checks if the given character is a digit or not. It is defined in the cctype header file. Example #include <iostream> using namespace std; int main() { // checks if '9' is a digit cout << isdigit('9'); return 0; } // Output: 1 Run Code ...
步骤3B:如果字符的 ASCII 值不在 48(即‘0’)和 57(即‘9’)之间, 零值 (FALSE)被退回。 由纯净天空筛选整理自sonunegi18559大神的英文原创作品isdigit() function in C/C++ with Examples。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。
The template function returns use_facet<ctype<CharType> >(_Loc).is(ctype<CharType>::digit, _Ch). Example 複製 // locale_is_digit.cpp // compile with: /EHsc #include <locale> #include <iostream> using namespace std; int main( ) { locale loc ( "German_Germany" ); bool result1 ...
isdigit Create account std::isdigit(std::locale) Defined in header<locale> template<classCharT> boolisdigit(CharT ch,constlocale&loc); Checks if the given character is classified as a digit by the given locale'sstd::ctypefacet. Parameters...
return c>='0' && c <='9';也通过优化转换为c-48 > 10（编译器执行的通用if x >= N && x...
By default, this function's global state is scoped to the application. To change this behavior, see Global state in the CRT.RequirementsProširi tabelu RoutineRequired header isdigit <ctype.h> iswdigit <ctype.h> or <wchar.h> _isdigit_l <ctype.h> _iswdigit_l <ctype.h> or <wcha...
7.4.1.5 The isdigit function (p: 201) C99 standard (ISO/IEC 9899:1999): 7.4.1.5 The isdigit function (p: 182) C89/C90 standard (ISO/IEC 9899:1990): 4.3.1.4 The isdigit function See also iswdigit (C95) checks if a wide character is a digit (function) ASCII values charact...
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std::isdigit(std::locale) Defined in header<locale> template<classcharT> boolisdigit(charT ch,constlocale&loc); Checks if the given character is classified as a digit by the given locale'sstd::ctypefacet. Parameters ch-character loc-locale ...