C

c string is int

int isNumber(char s[])
{
    for (int i = 0; s[i]!= ''; i++)
    {
        if (isdigit(s[i]) == 0)
              return 0;
    }
    return 1;
}

c check if character is a digit

char ch = '1';
if(isdigit(ch))
  printf("numeric");     
else
    printf("alphabet" );
 // output: numeric
CCopy