Example The following example shows the usage of isdigit function. Let us compile and run the above program, to produce the following result − int isdigit(int c); #include <stdio.h> #include <ctype.h>

Two types of strings in C++. C++ strings are represented with the string type. To use string, you must #include <string> at the top of your program. Despite the above syntax, C++ strings are not arrays; …

To test strings by using the methods isalnum, isalpha, isdigit, isidentifier, islower, isupper, and isspace (§8.2.9). To search for substrings by using the methods endswith, startswith, find, rfind, and count …

Character functions in C See <ctype.h> These return either 0 int isdigit(int c) int isalnum(int c) int islower(int c) int isspace(int c) int ispunct(int c) int isgraph(int c)

SYNOPSIS #include <ctype.h> int isalnum(int c); int isalpha(int c); int isascii(int c); int isblank(int c); int iscntrl(int c); int isdigit(int c); int isgraph(int c); int islower(int c); int isprint(int c); int ispunct(int c); int …

Explanation: The isdigit() method is a string method that returns True if all the characters in the string are digits (0-9), and the string is not empty. Otherwise, it returns False.

If the single character was a space (or other whitespace character, such as a tab), then isupper, islower, and isdigit would all return False. It should be pointed out that isupper and islower behave slightly …