check if char is alphanumeric c++ code example

Example 1: check if character in string is alphabet c++

#include<stdio.h>
#include<ctype.h>

int main() {
   char val1 = 's';
   char val2 = '8';

   if(isalpha(val1))
   printf("The character is an alphabet\n");
   else
   printf("The character is not an alphabet\n");

   if(isalpha(val2))
   printf("The character is an alphabet\n");
   else
   printf("The character is not an alphabet");

   return 0;
}

Example 2: c++ isalphanum

string test = "Ab4 :";
std::isalnum(test[0]);	//true
std::isalnum(test[1]);	//true
std::isalnum(test[2]);	//true
std::isalnum(test[3]);	//false
std::isalnum(test[4]);	//false