Birla Institute of Technology & Science, Pilani
Second Semester 2015-2016, CS F111 Computer Programming
Mid Semester Test (Open Book)
Date: March 13, 2016 Time: 11.00 - 12.30 PM Max. Marks: 75
[NOTE: Answer all parts of a question sequentially]
Q1. Attempt the following (sequentially) for two numbers Num1 = (-127)10 and Num2 = (127)8 [4x2 + 4 = 12M]
[NOTE: There is no interdependency among the following parts, i.e., for each part, take Num1 = (-127)10 and Num2 = (127)8].
a) Assuming 16-bit 2's complement number representation, convert Num1 and Num2 to Hexadecimal.
b) Assuming 15-bit 2's complement number representation, find Num3 (in octal representation), where
Num3 = Num1 - Num2. Here, you should clearly show the steps for finding Num3.
c) Assuming 9-bit sign magnitude number representation, convert Num2 to base-5 representation.
d) Assuming 1's complement representation, represent Num1 in binary using minimum number of bits.
e) For the following equation, what is the highest value of Num3 (in decimal) so that while calculating Num4
no overflow occurs. Assume 8-bit 2's complement number representation here.
Num4 = (Num1 XOR Num2) + Num3
Q2. Attempt the following sequentially [3+2+2 = 7M]
a) Write the decimal equivalent for the following IEEE floating point number:
1 01111101 10000000000000000000000
b) Write a single UNIX command to compile the C program 'first.c' and store the executable in file 'firstExe'.
c) Give a single UNIX command to remove a directory (named csf111) in the current folder if it is not empty.
Q3. Attempt the following five parts sequentially: [6x3 = 18M]
(a) What is the output of the
following? For float, consider a
precision of 2 digits.
int main() {
int a=25, b=7, c=15, d;
float m=12.5, x, y;
d = a + 3 / b * c;
x = (float) (a / b);
y = m * (b / c);
c = a + b / c;
printf ("%d %d %f %f", c, d, x, y);
return 0;
}
(d) What is the output
of the following?
int main()
{
int i=-2, j=3, k=0, m;
m = ++i - ++j + ++k;
printf("%d, %d\n", i, j);
printf("%d, %d ",k, m);
return 0;
}
(b) In the following program, replace
printf statement with an if-else
construct to produce the same
output.
int main()
{
int str[] = {1,2,3,4,5};
int a;
scanf ("%d",&a);
printf(a>10?"CP\n":"%d\n",str[4]);
return 0;
}
(c) How many times the
condition in the while
loop (i.e. j <= 255) will
be tested ?
int main() {
char j=1;
while(j <= 255) {
printf("%c %d\n", j, j);
j++;
}
return 0;
}
(e) The cell phone charges are computed per
minute with each partial minute being treated
as a full minute. For example if your call is for
75 seconds, you will be charged for 2 minutes
of use. Assume that an integer variable
talktimeinsecs stores the exact number of
seconds of a cell phone conversation. Write a
program fragment (not a complete program,
no declarations, no printf’s or scanf’s, . . . )
that assigns a value to the integer variable
talktimeinmins, consistent with the “partial
minute counts as full minute” policy.
(f) Given below is an incomplete program that reads an integer n and
computes and prints the term an where a1 = 1, a2 = 2, a3 = 3, and for k > 3 : ak
= ak−2 + 2 × ak−3. Assume n > 0. For ex: if n = 5, output is a_5 is 7. Complete it.
void main() {
int a_nMinus3 = 1, a_nMinus2= 2, a_nMinus1 = 3, a_n, n, i;
printf("Enter n: "); scanf("%d", &n);
if (n <= 3)
printf("a_%d is %d\n", n, n);
for (i = 3; i < n; i++)
{
//Write code here to complete your program.
//Just write these lines in your answer sheet
}
printf("a_%d is %d\n", n, a_n);
}
