CBSE Computer Science sample paper7 class XII 2008

http://www.cbseguess.com/SAMPLE PAPER -2008 Class -XII SUBJECT – COMPUTER SCIENCE 1. (a) Differentiate between a global variable and a local variable. (b) Name the Header file(s) that shall be needed for successful compilation of the following C++ code? void main() { char st[20]; gets(st); if(isaplha(st[0]) cout<<”Starts with alphabet”; else cout< #define SIZE =10 VOID MAIN() { int a[SIZE]={10,20,30,40,50}; float x=2; SIZE=5; for(int i=0;i #include struct Student { int rno; char name[20]; }; void main() { student a[2]={1,”Amit”,}{2,”Sumit”}}; for(int i=0;i<2;i++) { [1] [2] [2] [1] AATTOOMMIICC EENNEERRGGYY CCEENNTTRRAALL SSCCHHOOOOLL,, KKAAKKRRAAPPAARR II -Confidence Test Subject: Computer Sc. Class: XII Time: 3 Hours Date: 04.02.08 MM: 70 http://www.cbseguess.com/cout<<”\n Rno”< int a=10; void main() { void demo(int &,int,int*); int a=20,b=5; demo(::a,a,&b); cout<<::a< #include void main() { int r; randomize(); r=random(20)+random(2); cout<> Idno; gets(Type); gets(Desc);} void Showonscreen() { cout<=12000, with each department. VII. Give the output of following statement. (i) Select COUNT(distinct department) from TEACHER. (ii) Select name, MAX(Age) from Teacher where sex=”F” (b) Define the following terms in Database: (1) Set Difference (2) Foreign Key (c) (i) What is a View? Write syntax to create a view from a table. (ii) Differentiate between DDL and DML commands. [2] [1] [1] 7. (a) State and verify Demorgan‟s Laws (b)Write the equivalent Boolean expression for the following Circuit ( c) For the given truth table, give canonical sum-of-products(SOP) and canonical product-of-sum (POS) expression X Y Z F o/p 0 0 0 0 0 0 1 1 0 1 0 0 0 1 1 0 1 0 0 1 1 0 1 1 1 1 0 0 1 1 1 1 (d) If F(a,b,c,d)= Σ (1,3,4,5,7,9,11,12,13,15) obtain the simplified form using K-Map. (e) Write the principal of Duality and write the dual of the Boolean Expression: (B` + C) + A` [2] [1] [2] [2] [1] http://www.cbseguess.com/(f) Draw the Circuit for Boolean expression (X+Y)(Y+Z)(X+Z) with help of NOR gate only. [1] 8. (a) Write the different type of Topologies with one advantage and one disadvantage. (b) Define Circuit Switching and Packet Switching (c) Give one advantage and one disadvantage of optical fiber and coaxial cable used in communication. (d) Explain the following terms (1) Video Conferencing (2) TCP\IP (e) Knowledge Supplement Organization has set up its new center at Mangalore for its office and web based activities. It has 4 blocks of buildings as shown in the diagram below. The distances between the building are as : Block A to Block C-120 meters Block A to Block B-20 meters Block A to Block D-550 meters Block B to Block D-80 meters Block D to Block C-110 meters Block B to Block C-280 meters The number of computers in each Block are as follows: Block A -120 Block B -180 Block C -20 Block D -110 [3] [2] [1] [2] Block A Block C Block D Block B http://www.cbseguess.com/(i) Suggest a cable layout of connections between the blocks and type of cable. (ii) Suggest the most suitable place (i.e. block) to house the server of this organization with a suitable reason. (iii) Suggest the placement of the following devices with justification. (a) Repeater (b) Hub/Switch (iv) The organization is planning to link its front office situated in the city in a Hilly region where cable connection is not feasible, suggest an economic way to connect it with reasonably high speed. [1] [1] [1] [1]