C++ Locale Library - isdigit

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Description

It checks if character is decimal digit.

Declaration

Following is the declaration for std::isdigit.

C++98

 int isdigit ( int c ); 

C++11

 int isdigit ( int c ); 

Parameters

c − Character to be checked, casted to an int, or EOF.

Return Value

It returns a value different from zero.

Exceptions

No-throw guarantee − this function never throws exceptions.

Example

In below example for std::isdigit.

 #include <stdio.h> #include <stdlib.h> #include <ctype.h> int main () { char str[]="2016ad"; int year; if (isdigit(str[0])) { year = atoi (str); printf ("The year that followed %d was %d.\n",year,year+1); } return 0; } 

The sample output should be like this −

 The year that followed 2016 was 2017.