348、multimedia

267、The main hardcopy output devices are printers and plotters.A printer can print characters,symbols,and usually graphics on paper.Printers are categorized according to whether or not the image produced is formed by physical contact of the print mechanism with the paper.Impact printers make contact; nonimpact printers do not.Impact printers usually form images by pressing an inked ribbon against the paper with a hammer-like mechanism.A letter-quality printer,like a typewriter, presses fully formed characters against the ribbon.A dot一matrix printer uses separate pin-like hammers to form characters out of dot patterns.Letter-quality printers produce higher quality images than do dot-matrix printers and are generally used for business letters, important memos, and reports.However, letter-quality printers are slower and noisier than dot-matrix printers, and they cannot produce graphics.Common types of impact letter-quality printers are the daisy wheel printer, the thimble printer, and the ball printer.Dot-matrix printer, because they do not print fully formed characters, are more flexible and can be used to print graphics in black or in color.The high-volume output requirements of most large computer installations cannot be satisfied by dot-matrix or letter-quality printers.Large computer systems often use special high-speed printers, called line printers that print a whole line at a time.Three common types of line printers are drum printers,band or belt printers,and chain printers.Laser printers are nonmechanical, nonimpact printers.Because the process has no print heads that move or print hammers that fire,the result is high speed and quiet operation.Laser printers work somewhat like photocopying machines.They use laser beams to transfer images to sensitive paper that is then coated with toner, the toner sticks to the spots sensitized by the laser.Laser printers print a page at a time and can produce very high quality images, so they are often used for graphics.(4)、Which of the following is not a Common types of impact letter-quality printers?Common type of impact letter-quality printer? are the daisy wheel printer, the thimble printer, and the ball printer.

267、The main hardcopy output devices are printers and plotters.A printer can print characters,symbols,and usually graphics on paper.Printers are categorized according to whether or not the image produced is formed by physical contact of the print mechanism with the paper.Impact printers make contact; nonimpact printers do not.Impact printers usually form images by pressing an inked ribbon against the paper with a hammer-like mechanism.A letter-quality printer,like a typewriter, presses fully formed characters against the ribbon.A dot一matrix printer uses separate pin-like hammers to form characters out of dot patterns.Letter-quality printers produce higher quality images than do dot-matrix printers and are generally used for business letters, important memos, and reports.However, letter-quality printers are slower and noisier than dot-matrix printers, and they cannot produce graphics.Common types of impact letter-quality printers are the daisy wheel printer, the thimble printer, and the ball printer.Dot-matrix printer, because they do not print fully formed characters, are more flexible and can be used to print graphics in black or in color.The high-volume output requirements of most large computer installations cannot be satisfied by dot-matrix or letter-quality printers.Large computer systems often use special high-speed printers, called line printers that print a whole line at a time.Three common types of line printers are drum printers,band or belt printers,and chain printers.Laser printers are nonmechanical, nonimpact printers.Because the process has no print heads that move or print hammers that fire,the result is high speed and quiet operation.Laser printers work somewhat like photocopying machines.They use laser beams to transfer images to sensitive paper that is then coated with toner, the toner sticks to the spots sensitized by the laser.Laser printers print a page at a time and can produce very high quality images, so they are often used for graphics.(3)、How are printers classified?

267、The main hardcopy output devices are printers and plotters.A printer can print characters,symbols,and usually graphics on paper.Printers are categorized according to whether or not the image produced is formed by physical contact of the print mechanism with the paper.Impact printers make contact; nonimpact printers do not.Impact printers usually form images by pressing an inked ribbon against the paper with a hammer-like mechanism.A letter-quality printer,like a typewriter, presses fully formed characters against the ribbon.A dot一matrix printer uses separate pin-like hammers to form characters out of dot patterns.Letter-quality printers produce higher quality images than do dot-matrix printers and are generally used for business letters, important memos, and reports.However, letter-quality printers are slower and noisier than dot-matrix printers, and they cannot produce graphics.Common types of impact letter-quality printers are the daisy wheel printer, the thimble printer, and the ball printer.Dot-matrix printer, because they do not print fully formed characters, are more flexible and can be used to print graphics in black or in color.The high-volume output requirements of most large computer installations cannot be satisfied by dot-matrix or letter-quality printers.Large computer systems often use special high-speed printers, called line printers that print a whole line at a time.Three common types of line printers are drum printers,band or belt printers,and chain printers.Laser printers are nonmechanical, nonimpact printers.Because the process has no print heads that move or print hammers that fire,the result is high speed and quiet operation.Laser printers work somewhat like photocopying machines.They use laser beams to transfer images to sensitive paper that is then coated with toner, the toner sticks to the spots sensitized by the laser.Laser printers print a page at a time and can produce very high quality images, so they are often used for graphics.(2)、Which of the following statements about laser printers is wrong?

267、The main hardcopy output devices are printers and plotters.A printer can print characters,symbols,and usually graphics on paper.Printers are categorized according to whether or not the image produced is formed by physical contact of the print mechanism with the paper.Impact printers make contact; nonimpact printers do not.Impact printers usually form images by pressing an inked ribbon against the paper with a hammer-like mechanism.A letter-quality printer,like a typewriter, presses fully formed characters against the ribbon.A dot一matrix printer uses separate pin-like hammers to form characters out of dot patterns.Letter-quality printers produce higher quality images than do dot-matrix printers and are generally used for business letters, important memos, and reports.However, letter-quality printers are slower and noisier than dot-matrix printers, and they cannot produce graphics.Common types of impact letter-quality printers are the daisy wheel printer, the thimble printer, and the ball printer.Dot-matrix printer, because they do not print fully formed characters, are more flexible and can be used to print graphics in black or in color.The high-volume output requirements of most large computer installations cannot be satisfied by dot-matrix or letter-quality printers.Large computer systems often use special high-speed printers, called line printers that print a whole line at a time.Three common types of line printers are drum printers,band or belt printers,and chain printers.Laser printers are nonmechanical, nonimpact printers.Because the process has no print heads that move or print hammers that fire,the result is high speed and quiet operation.Laser printers work somewhat like photocopying machines.They use laser beams to transfer images to sensitive paper that is then coated with toner, the toner sticks to the spots sensitized by the laser.Laser printers print a page at a time and can produce very high quality images, so they are often used for graphics.(1)、Which of the following is not a common type of line printer?

266、In computer science an array is a data structure consisting of a group of elements that are accessed by indexing.In most programming languages each element has the same data type and the array occupies a contiguous area of storage.Most programming languages have a built-in array data type , although what is called an array in the language documentation is sometimes really an associative array.Conversely, the contiguous storage kind of array discussed here may alternatively be called a vector, list , or table.Some programming languages support array programming ( ) which generalizes operations and functions to work transparently over arrays as they do with scalars, instead of requiring looping over array members.Multi-dimensional arrays are accessed using more than one index:one for each dimension.Arrays can be classified as fixed-sized arrays ( ) whose size cannot change once their storage has been allocated or dynamic arrays, which can be resized.Fixed-size arrays permit efficient random access.They are compact data structures, having a constant memory overhead.And, on CPUs which support caches sequential iteration over an array has good locality of reference because its elements occupy contiguous memory locations.However, when an array is randomly accessed , for example when probing a hash table, locality of reference may be lost.(5)、 What is the main point of this text?

266、In computer science an array is a data structure consisting of a group of elements that are accessed by indexing.In most programming languages each element has the same data type and the array occupies a contiguous area of storage.Most programming languages have a built-in array data type , although what is called an array in the language documentation is sometimes really an associative array.Conversely, the contiguous storage kind of array discussed here may alternatively be called a vector, list , or table.Some programming languages support array programming ( ) which generalizes operations and functions to work transparently over arrays as they do with scalars, instead of requiring looping over array members.Multi-dimensional arrays are accessed using more than one index:one for each dimension.Arrays can be classified as fixed-sized arrays ( ) whose size cannot change once their storage has been allocated or dynamic arrays, which can be resized.Fixed-size arrays permit efficient random access.They are compact data structures, having a constant memory overhead.And, on CPUs which support caches sequential iteration over an array has good locality of reference because its elements occupy contiguous memory locations.However, when an array is randomly accessed , for example when probing a hash table, locality of reference may be lost.(4)、Which programming languages do not support array programming

266、In computer science an array is a data structure consisting of a group of elements that are accessed by indexing.In most programming languages each element has the same data type and the array occupies a contiguous area of storage.Most programming languages have a built-in array data type , although what is called an array in the language documentation is sometimes really an associative array.Conversely, the contiguous storage kind of array discussed here may alternatively be called a vector, list , or table.Some programming languages support array programming ( ) which generalizes operations and functions to work transparently over arrays as they do with scalars, instead of requiring looping over array members.Multi-dimensional arrays are accessed using more than one index:one for each dimension.Arrays can be classified as fixed-sized arrays ( ) whose size cannot change once their storage has been allocated or dynamic arrays, which can be resized.Fixed-size arrays permit efficient random access.They are compact data structures, having a constant memory overhead.And, on CPUs which support caches sequential iteration over an array has good locality of reference because its elements occupy contiguous memory locations.However, when an array is randomly accessed , for example when probing a hash table, locality of reference may be lost.(3)、Which of the following statements is wrong

266、In computer science an array is a data structure consisting of a group of elements that are accessed by indexing.In most programming languages each element has the same data type and the array occupies a contiguous area of storage.Most programming languages have a built-in array data type , although what is called an array in the language documentation is sometimes really an associative array.Conversely, the contiguous storage kind of array discussed here may alternatively be called a vector, list , or table.Some programming languages support array programming ( ) which generalizes operations and functions to work transparently over arrays as they do with scalars, instead of requiring looping over array members.Multi-dimensional arrays are accessed using more than one index:one for each dimension.Arrays can be classified as fixed-sized arrays ( ) whose size cannot change once their storage has been allocated or dynamic arrays, which can be resized.Fixed-size arrays permit efficient random access.They are compact data structures, having a constant memory overhead.And, on CPUs which support caches sequential iteration over an array has good locality of reference because its elements occupy contiguous memory locations.However, when an array is randomly accessed , for example when probing a hash table, locality of reference may be lost.(2)、Which of the following statements about array is correct?

266、In computer science an array is a data structure consisting of a group of elements that are accessed by indexing.In most programming languages each element has the same data type and the array occupies a contiguous area of storage.Most programming languages have a built-in array data type , although what is called an array in the language documentation is sometimes really an associative array.Conversely, the contiguous storage kind of array discussed here may alternatively be called a vector, list , or table.Some programming languages support array programming ( ) which generalizes operations and functions to work transparently over arrays as they do with scalars, instead of requiring looping over array members.Multi-dimensional arrays are accessed using more than one index:one for each dimension.Arrays can be classified as fixed-sized arrays ( ) whose size cannot change once their storage has been allocated or dynamic arrays, which can be resized.Fixed-size arrays permit efficient random access.They are compact data structures, having a constant memory overhead.And, on CPUs which support caches sequential iteration over an array has good locality of reference because its elements occupy contiguous memory locations.However, when an array is randomly accessed , for example when probing a hash table, locality of reference may be lost.(1)、Which of the following statements about array programming is correct?

265、The application layer provides an interface for the operating system or network applications to network services.