Turbo Basic

Line 1, Column 1 Columns (1-80)80~Lme 25 Reserved for Soft key DIsplay 7/Figure 4-2Text Mode Screen• 25Lme 25, Column 80Generally speaking, you place characters on the screen by moving the cursor tothe desired position with the LOCATE statement and then using PRINT. Exoticcharacters that are difficult to generate at the keyboard can be produced with theCHR$ function (see Appendix F).The 25th (lowest) line of the screen rates special consideration: The KEY statementloads it with function key descriptions ("soft keys"). To protect these keydescriptions, the 25th line is never scrolled or written to unless you tum off thefunction key display with KEY OFF.For monochrome adapters, the COLOR statement can be used to create specialeffects such as inverse and reduced intensity video and underlined and/or blinkingtext. With a CGA/EGA adapter, the COLOR statement is used to select the actualcolor to be displayed for output from PRINT statements.In text mode, the CGA/EGA adapters support up to eight display "pages"; thepage being processed and/or displayed is set with the SCREEN statement.The Graphics ModesTurbo Basic has a full complement of commands to plot points, lines, and graphicshapes on the screen in various colors. Unless you have appropriate video displayhardware, such as the Color/Graphics Adapter or the Enhanced Graphics Adapteror equivalent, these commands won't work as described. (In general, attempting touse a graphics command on text-only hardware produces an Illegal Function Callerror.)In graphics modes, the screen is treated as a grid of small dots, or pixels, anyoneof which can be turned on (white or some color), or off (the background color,usually black). The pixels are identified by their position on an (x,y) grid, the originTurbo Basic: The LanguageIII