在C / C的wmemchr()函数在++的宽字符块找到字符。此函数在ptr所指向的块的前num个字符内搜索ch的首次出现,并返回指向它的指针。
句法:
const wchar_t* wmemchr( const wchar_t* ptr, wchar_t ch, size_t num )
or
wchar_t* wmemchr( wchar_t* ptr, wchar_t ch, size_t num )
参数:该函数接受三个强制性参数,如下所述:
- ptr:指定要搜索的字符数组的指针。
- ch:指定要定位的字符。
- num:指定要比较的wchar_t类型的元素数。
返回值:该函数返回两个值,如下所示:
- 成功时,它将返回一个指向字符数组位置的指针。
- 否则,返回NULL指针。
下面的程序说明了上述函数:
计划1:
C++
// C++ program to illustrate
// wmemchr() function
#include
using namespace std;
int main()
{
// initialize the string to be scanned
wchar_t ptr[] = L"GeeksForGeeks";
// character to be searched for
wchar_t ch = L'o';
// length, till the character to be search for is 8
// run the function to check if the character is present
bool look = wmemchr(ptr, ch, 8);
if (look)
wcout << "'" << ch << "'" << L" is present in first "
<< 8 << L" characters of \"" << ptr << "\"";
else
wcout << "'" << ch << "'" << L" is not present in first "
<< 8 << L" characters of \"" << ptr << "\"";
return 0;
}
C++
// C++ program to illustrate
// wmemchr() function
#include
using namespace std;
int main()
{
// initialize the string to be scanned
wchar_t ptr[] = L"GFG";
// character to be searched for
wchar_t ch = L'p';
// length, till the character to be search for is 3
// run the function to check if the character is present
bool look = wmemchr(ptr, ch, 3);
if (look)
wcout << "'" << ch << "'" << L" is present in first "
<< 3 << L" characters of \"" << ptr << "\"";
else
wcout << "'" << ch << "'" << L" is not present in first "
<< 3 << L" characters of \"" << ptr << "\"";
return 0;
}
输出:
'o' is present in first 8 characters of "GeeksForGeeks"
程序2:
C++
// C++ program to illustrate
// wmemchr() function
#include
using namespace std;
int main()
{
// initialize the string to be scanned
wchar_t ptr[] = L"GFG";
// character to be searched for
wchar_t ch = L'p';
// length, till the character to be search for is 3
// run the function to check if the character is present
bool look = wmemchr(ptr, ch, 3);
if (look)
wcout << "'" << ch << "'" << L" is present in first "
<< 3 << L" characters of \"" << ptr << "\"";
else
wcout << "'" << ch << "'" << L" is not present in first "
<< 3 << L" characters of \"" << ptr << "\"";
return 0;
}
输出:
'p' is not present in first 3 characters of "GFG"
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