SECTION F- PRIMER                                     FILE PRIMER.F
                                        STRINGS
                                        *******

          A 'STRING' is simply a set of one or more characters put together. 
          Some examples are :

                  "A"
                  "Have a nice day!"
                  "Joe Murphy"
                  "123456"
                  "14th September 1956"
                  "Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov"
                  "#14.00"
                  ""

          I have put these examples inside double quotes not only to show them 
          better, but also because they are often required to be in this form 
          in a program.The last example shows nothing between the quote marks, 
          not even a space.It is a special case and is known as a NULL STRING.

          We have already met 'STRINGS'; in section a where we saw how strings 
          were used with the PRINT command ,and in section c where we saw that 
          a string can be represented by a STRING VARIABLE.

          At first you may not see the reason why strings are enclosed in 
          double quotes and numbers and variables are not, but as you come to 
          use BASIC more the logic of it will become apparent. The double 
          quotes tell the computer that the group of characters is, in fact, a 
          string and to treat it accordingly. For this reason a string cannot 
          contain a double quote mark or the machine will become confused. If 
          for example we wrote " The boy said "hello" and walked on", the 
          computer would see this as two strings - "The boy said ", and "and 
          walked on". The word 'hello' in the middle would confuse it 
          completely as it doesn't have double quotes of it's own, and would 
          result in an error message being displayed. A simple way to get over 
          this is to use single quotes instead and to write ;
                  "The boy said 'hello' and walked on "

          The manipulation of strings is a major part of programming and 
          strings can be concatenated (added), parts of strings can be taken 
          away, strings can be examined to see whether they contain certain 
          characters, and so on. Treatment of text is only one facet of the 
          manipulation of strings and you will see that strings and string 
          variables combine to make the computer language very  powerful.

          The next listing demonstrates concatenation in various ways

          End of file PRIMER.F
           
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