The iswdigit() is a built-in function in C++ STL which checks if the given wide character is an decimal digit character or not. It is defined within the cwctype header file of C++. The characters from 0 to 9 i.e.0, 1, 2, 3, 4, 5, 6, 7, 8, 9 are classified as decimal digits.
Parameter: The function accepts a single mandatory parameter ch which specifies the wide character which we have to check that if it is a digit or not.
Return Value: The function returns two values as shown below.
- If the ch is a digit, then a non-zero value is returned.
- If it is not then 0 is returned.
Below programs illustrates the above function.
? is not a digit 3 is a digit
1 is a digit q is not a digit
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