"C" style functions, tricks and magic

String functions:
   strlen()    Get length of a string.
   strcpy()    Copy one string to another.
   strcat()    Link together (concatenate) two strings.
   strcmp()    Compare two strings.
   strchr()    Find character in string.
   strstr()    Find string in string.
   strlwr()    Convert string to lowercase.
   strupr()    Convert string to uppercase.

EXAMPLES:
   int  len, rval ;
   char strOne[256], strTwo[256], subStr[256];

   len = strlen( strOne );           //  len is length of strOne.
   strcpy( strOne, strTwo );         //  Copy strTwo over strOne.
   strcat( strOne, strTwo);          //  Concatenate strTwo at end of strOne.
   rval  = strcmp( strOne,strTwo );  //  rval zero if strings match.
   rval  = strchr( strOne, 'Z');     //  rval is offset of Z in strOne.
   rval  = strstr (strOne,subStr);   //  rval is offset of subStr in strOne
   strlwr( strOne );                 //  Convert strOne to lowercase.
   strupr( strOne );                 //  Convert strOne to uppercase.

	
   Code example for converting a string to upper or lower:

    char name[80]; 
    memset(name,0, sizeof(name));
    cout << "Enter in a name in lowercase:";
    cin >> name;
    strupr(name);
    cout << "The name in uppercase is: " << name << endl;
    strlwr(name);
    cout << "The name in lowercase is: " << name << endl;
	
ASCII or string to integer conversion:

    int line;
    char tstring[22] = "345";
    line = atoi ( tstring );	 //  line now has value 345


Character Functions:
   isupper()    is a character upper case ?
   islower()    is a character lower case ?
   isdigit()    is a character a digit ?
   isalpha()    is a character a letter ?

Example code fragments:
   int rval;
   char testStr[64] = "How now brown cow";
   rval = isupper( testStr[0] );    // is a character upper case ?  YES
   rval = islower( testStr[0] );    // is a character lower case ?  NO
   rval = isdigit( testStr[0] );    // is a character a digit ?     NO
   rval = isalpha( testStr[0] );    // is a character a letter ?    YES