// atoi and strcpy
  int val;
   char str[20];
  
   strcpy(str, "98993489");
   val = atoi(str);
   printf("String value = %s, Int value = %d\n", str, val);

   strcpy(str, "csc215");
   val = atoi(str);
   printf("String value = %s, Int value = %d\n", str, val);
   
   
   //strlen
   char str[50];
   int len;

   strcpy(str, "csc215");

   len = strlen(str);
   printf("Length of |%s| is |%d|\n", str, len);
   
  
  //strcat
   char src[50], dest[50];

   strcpy(src,  "This is source");
   strcpy(dest, "This is destination");

   strcat(dest, src);

   printf("Final destination string : |%s|\n", dest);
   
   //strncat
   strncat(dest, src, 15);
   printf("Final destination string : |%s|\n", dest);
  
  //strcmp
  
  char str1[15];
   char str2[15];
   int ret;


   strcpy(str1, "abcdef");
   strcpy(str2, "ABCDEF");

   ret = strcmp(str1, str2);

   if(ret > 0)
   {
      printf("str1 is less than str2");
   }
   else if(ret < 0) 
   {
      printf("str2 is less than str1");
   }
   else 
   {
      printf("str1 is equal to str2");
   }

 //strncmp
 
  ret = strncmp(str1, str2, 4);

   if(ret > 0)
   {
      printf("str1 is less than str2");
   }
   else if(ret < 0) 
   {
      printf("str2 is less than str1");
   }
   else 
   {
      printf("str1 is equal to str2");
   }
   
   // strncpy
   char src[40];
   char dest[12];
  
   memset(dest, '\0', sizeof(dest));
   strcpy(src, "csc215");
   strncpy(dest, src, 10);

   printf("Final copied string : %s\n", dest);
   
   // strchr
   const char str[] = "csc215";
   const char ch = 's';
   char *ret;

   ret = strchr(str, ch);

   printf("String after |%c| is - |%s|\n", ch, ret);
   
   //strrchr
   int len;
   const char str[] = "csc215";
   const char ch = 's';
   char *ret;

   ret = strrchr(str, ch);

   printf("String after |%c| is - |%s|\n", ch, ret);
   
   //strstr
   const char haystack[20] = "csc215";
   const char needle[10] = "215";
   char *ret;

   ret = strstr(haystack, needle);

   printf("The substring is: %s\n", ret);
   
   //
   
    const char* s1= "Hello World";
    char* new = strdup (s1);
    printf("The old %s and the new %s /n",*s1, *new)
    
    //isalnum
    int var1 = 'd';
   int var2 = '2';
   int var3 = '\t';
   int var4 = ' ';
    
   if( isalnum(var1) )
   {
      printf("var1 = |%c| is alphanumeric\n", var1 );
   }
   else
   {
      printf("var1 = |%c| is not alphanumeric\n", var1 );
   }
   if( isalnum(var2) )
   {
      printf("var2 = |%c| is alphanumeric\n", var2 );
   }
   else
   {
      printf("var2 = |%c| is not alphanumeric\n", var2 );
   }
   if( isalnum(var3) )
   {
      printf("var3 = |%c| is alphanumeric\n", var3 );
   }
   else
   {
      printf("var3 = |%c| is not alphanumeric\n", var3 );
   }
   if( isalnum(var4) )
   {
      printf("var4 = |%c| is alphanumeric\n", var4 );
   }
   else
   {
      printf("var4 = |%c| is not alphanumeric\n", var4 );
   }
   
   //isalpha
   if( isalpha(var1) )
   {
      printf("var1 = |%c| is an alphabet\n", var1 );
   }
   else
   {
      printf("var1 = |%c| is not an alphabet\n", var1 );
   }
   if( isalpha(var2) )
   {
      printf("var2 = |%c| is an alphabet\n", var2 );
   }
   else
   {
      printf("var2 = |%c| is not an alphabet\n", var2 );
   }
   if( isalpha(var3) )
   {
      printf("var3 = |%c| is an alphabet\n", var3 );
   }
   else
   {
      printf("var3 = |%c| is not an alphabet\n", var3 );
   }
   if( isalpha(var4) )
   {
      printf("var4 = |%c| is an alphabet\n", var4 );
   }
   else
   {
      printf("var4 = |%c| is not an alphabet\n", var4 );
   }
   
   //isdigit
   if( isdigit(var1) )
   {
      printf("var1 = |%c| is a digit\n", var1 );
   }
   else
   {
      printf("var1 = |%c| is not a digit\n", var1 );
   }
   if( isdigit(var2) )
   {
      printf("var2 = |%c| is a digit\n", var2 );
   }
   else
   {
      printf("var2 = |%c| is not a digit\n", var2 );
   }
   
   // islower
   int var1 = 'Q';
   int var2 = 'q';
   int var3 = '3';
    
   if( islower(var1) )
   {
       printf("var1 = |%c| is lowercase character\n", var1 );
   }
   else
   {
      printf("var1 = |%c| is not lowercase character\n", var1 );
   }
   if( islower(var2) )
   {
       printf("var2 = |%c| is lowercase character\n", var2 );
   }
   else
   {
      printf("var2 = |%c| is not lowercase character\n", var2 );
   }
   if( islower(var3) )
   {
       printf("var3 = |%c| is lowercase character\n", var3 );
   }
   else
   {
      printf("var3 = |%c| is not lowercase character\n", var3 );
   }
   
   //ispunct
    int var1 = 't';
   int var2 = '1';
   int var3 = '/';
   int var4 = ' ';

   if( ispunct(var1) )
   {
       printf("var1 = |%c| is a punctuation character\n", var1 );
   }
   else
   {
       printf("var1 = |%c| is not a punctuation character\n", var1 );
   }
   if( ispunct(var2) )
   {
       printf("var2 = |%c| is a punctuation character\n", var2 );
   }
   else
   {
       printf("var2 = |%c| is not a punctuation character\n", var2 );
   }
   if( ispunct(var3) )
   {
       printf("var3 = |%c| is a punctuation character\n", var3 );
   }
   else
   {
       printf("var3 = |%c| is not a punctuation character\n", var3 );
   }
   if( ispunct(var4) )
   {
       printf("var4 = |%c| is a punctuation character\n", var4 );
   }
   else
   {
       printf("var4 = |%c| is not a punctuation character\n", var4 );
   }
   
   //isspace
   int var1 = 't';
   int var2 = '1';
   int var3 = ' ';

   if( isspace(var1) )
   {
       printf("var1 = |%c| is a white-space character\n", var1 );
   }
   else
   {
       printf("var1 = |%c| is not a white-space character\n", var1 );
   }
   if( isspace(var2) )
   {
       printf("var2 = |%c| is a white-space character\n", var2 );
   }
   else
   {
       printf("var2 = |%c| is not a white-space character\n", var2 );
   }
   if( isspace(var3) )
   {
       printf("var3 = |%c| is a white-space character\n", var3 );
   }
   else
   {
       printf("var3 = |%c| is not a white-space character\n", var3 );
   }
   
   // isupper
    int var1 = 'M';
   int var2 = 'm';
   int var3 = '3';
    
   if( isupper(var1) )
   {
      printf("var1 = |%c| is uppercase character\n", var1 );
   }
   else
   {
      printf("var1 = |%c| is not uppercase character\n", var1 );
   }
   if( isupper(var2) )
   {
      printf("var2 = |%c| is uppercase character\n", var2 );
   }
   else
   {
      printf("var2 = |%c| is not uppercase character\n", var2 );
   }   
   if( isupper(var3) )
   {
      printf("var3 = |%c| is uppercase character\n", var3 );
   }
   else
   {
      printf("var3 = |%c| is not uppercase character\n", var3 );
   }
   
   //toupper
   
    int i = 0;
   char c;
   char str[] = "csc 215";
   
   while(str[i])
   {
      putchar (toupper(str[i]));
      i++;
   }
   
   //tolower
   int i = 0;
   char c;
   char str[] = "CSC 215";
   while(str[i])
   {
      putchar (toupper(str[i]));
      i++;
   }