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Half Yearly Examination 2009
Subject : Computer Science Class :Class XI
Time Allowed : 3 hours Maximum Marks: 70 General Instructions:
(i) All questions are compulsory. (ii) Programming Language: C++
1. (a) What do you mean by abstraction and encapsulation? How are these two terms interrelated? 2 (b) Name the other header files that shall be needed for the
following code: 1 #include <iostream> using namespace std; int main() { char ch='b'; int x=45; x = log10(x); cout<<ch<<setw(15)<<"HEllo"; return 0; }
(c) Rewrite the following program after removing the syntactical errors(if any). Underline each correction. 2
#include <iostream> using namespace std; int main() { char ch='b'; int x=45;
if x>30 x--; for(;;) break; cout>>"Hello"; while (6) break; cin>>ch; ++x--; ch=c; return 0; }
(d) Find the output of the following C++ program. 3 #include <iostream> using namespace std; int main() { int x=45; for(;x>20;x+=4) { if(x%5==0) cout<<x<<endl; else continue; if(!(x%7)) break; } cout<<x<<endl; return 0; }
(e) In the following program, find the correct possible output(s) from the optons: 2 #include <iostream> #include <math.h> using namespace std; int main() { int y=0;
while(y<=10) { int x =1; do{ x++; if(y%x==0) cout<<"*"; if(x%3==2) cout<<"#"; }while(x<3); y+=6; cout<<"%"; } return 0; } (i) #%#% (ii) *#*%*#*% (iii) **%**% (iv) **#%**#%
(f) Find the output of the following C++ program. 2 int main(){ int y=0; for(int x=50;x>20;x-=5) { switch(x) { case 20: y=y+x; break; case 25: y = y +5; break; case 30: y = y+10; break; case 35: y =y+x; case 40: y =y+3; x=x-5; break; case 45:
y=y+2; break; case 50: x =x-5; default: x=x-5; } cout<<(x+y)<<endl; } return 0; }
2 (a) The size of storage devices BD and CD is same but
capacity differs. Why? 2
(b) Convert (i) 2MB to Bytes (ii) 3.5X235 Byte to GB 2 (c) Convert following numbers. 4
(i) 725.250 decimal number into binary number
(ii) 111011.00101 binary number into decimal number (iii) 1FF.1A Hexadecimal number into decimal number (iv) -177 into 2’s complement number in 8 bit format (d) Explain UNICODE and ASCII code. 2
(e) Write short note on Flash memories with one example.2 3. (a) Define (i) Time sharing operating system (ii) Real time
operating systems (iii) BOSS 3 (b) Write a C++ program that takes 3 numbers as input,
arrange them in ascending order and display back to user. For example if input is 6 8 3 then output should be 3 6 8. 3 (c) Write a C++ program that take a year as input print
whether the year is leap year or not. 2 (d) Write the C++ program using loop to print the following
pattern. One statement should print one character at
time. 2 *****# ****# ***# **# *#
#
(e) Write a C++ program that takes a number as input and print reverse of that number. For example if input is 4523 then output will be 3254. 3 (f) Declare following variables. 3
(i) An Integer constant (ii) A double constant (iii) A reference variable to float (iv) A pointer to character (v) An integer array of 10 items (vi) An unsigned integer 4. (a) Explain types of errors with one example of each. 4
(b) Give some stylistic guidelines for good program. 3 (c) Define Inheritance and Polymorphism. 2 (d) Define Lexical unit in C++. 1 5. (a) Write “Valid” if the following C++ identifiers are valid else
write “Invalid”. 3
(i) register (ii) class1 (iii) _34Name
(iv) Emp-name (v) one_to_two (vi) break3 (b) Write equivalent C++ statement for following mathematics
statements. 2 (i) b a b a + (ii) y x y x 3 5 3 5 −
+ (iii) |sin2(Ø) – cos2(Ø)| (iv) (a2+b2)35
(c) What is the effects of comments on complier. 1 (d) Explain the purpose of insertion and extraction operators
in C++. 2
6. (a) What is the difference between pointers and reference variables? Explain with the help of examples. 2 (b) Write C++ program to calculate area of a triangle. Take
the required parameters as input from user. Area of
triangle = s(s-a)(s-b)(s-c) where s=(a+b+c)/2 and a, b and c
are side of triangle. 2
(c) What is difference among structure, array and class? 3 7. (a) Write a C++ program that takes two numbers as input and
print all the even number between these numbers and
(b) Write a C++ program to print a menu and calculate area, perimeter and diagonal of a rectangle based on user
choice. 3
This paper contains 7 question and 5 printed pages
Scoring Key
Q.No Answer Hint
1.(a) (i) abstraction—1 Mark (ii)encapsulation—1 Mark
(b) Two header files—math.h—1/2 mark and iomanip.h—1/2 mark (c) 4 errors X ½ = 2 marks
(d) Processing steps – 2 marks output--45 65 85 105 105—1 mark (e) Processing –1 mark output--#%#%--1 marks
(f) Processing—1 mark 48 68 68—1 mark
2.(a) Two difference- 1marks for one difference (b) 2 conversion—2 marks one for each conversion (c) 4 conversion—4X1=4 marks one for each conversion (d) UNICODE—1 marks, ASCII—1 mark
(e) Explaination—1mark, example—1 mark
3.(a) Three operating system—3 marks one for each operating systems. (b) Structure— ½ mark, Indentation— ½ mark, logic-2 marks
(c) Structure— ½ mark, Indentation— ½ mark, logic-1 marks (d) Structure— ½ mark, Indentation— ½ mark, logic-1 marks (e) Structure— ½ mark, Indentation— ½ mark, logic-2 marks (f) 6 declaration X ½ = 3 marks
4.(a) Name of errors –1 mark, Explanations—2 marks, example—1 mark (b) Three points X1 mark—3 marks
(c) Inheritance –1 mark, Polymorphism—1 mark (d) Definition –1 mark
5.(a) 6 declaration X ½ mark—3 marks (b) 4 statements X ½ mark—2 marks (c) One effect—1 mark
(d) Insertion—1 mark, extraction—1 mark 6.(a) Difference—1mark, example—1mark
(b) Structure— ½ mark, Indentation— ½ mark, logic-2 marks (c) Structure—1mark, array—1mark and class—1mark
Chapter VSA SA LA Total No. of Ques. M. M. Total No. of Ques. M. M. Total No. of Ques. M. M. Total No. of Ques. Total Computer Overview 2 1 2 2 2 Working with operating system 3 1 3 3 3 Data representation 6 1 6 6 6 Input, output and Memory Devices 2 2 4 2 4 General Object oriented concepts 2 2 4 2 4 Getting started with C++ 2 1 2 1 2 2 3 4 Data handling 6 1 6 1 3 3 7 9 Operators and expressions in C++ 3 1 3 2 2 4 5 7 Flow of Control 6 2 12 4 3 12 10 24 Programming Methodology 1 3 3 1 4 4 2 7 Total 32 - 42 8 - 21 2 - 7 42 70
