4. A text search system set forth in claim 1, characterized in that said filtering means include leading character flag storage means for setting a value indicating "ON" in a slot corresponding to a leading character code of a search term designated previously while setting a value indicating "OFF" in slots corresponding to the other character codes, and trailing character flag storage means for setting a value indicating "ON" in slots corresponding to other character codes than said leading character code of those character codes which are included in said search term while setting a value indicating "OFF" in slots corresponding to the other character code; and that said system further comprises output select means for referencing said leading character flag storage means and said trailing character flag storage means in correspondence to a character code inputted from said character string storage means to thereby output the character code to said character string matching means only when the relevant leading character flag as read out is "ON", while when said leading character flag once assumed "ON", said output select means outputs an input character code to said character string matching means only when either the relevant leading character flag or trailing character flag is "ON" before both of said leading character flag and said trailing character flag become "OFF".
4. A text search system set forth in claim 1, characterized in that said filtering means include leading character flag storage means for setting a value indicating "ON" in a slot corresponding to a leading character code of a search term designated previously while setting a value indicating "OFF" in slots corresponding to the other character codes, and trailing character flag storage means for setting a value indicating "ON" in slots corresponding to other character codes than said leading character code of those character codes which are included in said search term while setting a value indicating "OFF" in slots corresponding to the other character code; and that said system further comprises output select means for referencing said leading character flag storage means and said trailing character flag storage means in correspondence to a character code inputted from said character string storage means to thereby output the character code to said character string matching means only when the relevant leading character flag as read out is "ON", while when said leading character flag once assumed "ON", said output select means outputs an input character code to said character string matching means only when either the relevant leading character flag or trailing character flag is "ON" before both of said leading character flag and said trailing character flag become "OFF". 5. A text search system set forth in claim 4, characterized in that said output select means further includes delimiter code output means for outputting a particular delimiter code to said character string matching means only when said leading character flag and trailing character flag corresponding to character codes as inputted are "OFF" and when said leading character flag and trailing character flag corresponding to character codes inputted in precedence by one character are "ON".