CMSC 202 Spring 2003
Lab Assignment 2

Name:_____________________________________ Checked:__________________________________

SSN:______________________________________ Date:_____________________________________

Purpose

1. Introduction to the use of strings, vectors and streams.
2. Formatting of output.

The Assignment

1. Logon on to your GL account.
   (Note: Please log on to the Linux machines, i.e., when you telnet or ssh, make sure the machine name is linux.gl.umbc.edu. Do not log on to the Irix machines.)
2. Create a directory called lab2 for this week's lab. This should most conveniently be ~/cs202/labs/lab2.
3. Copy the file /afs/umbc.edu/users/a/n/aniket1/pub/202/labs/lab2/floats.dat to this directory. This file contains a series of floating-point numbers, one per line, to be used for this lab.
4. Write a program in the file floats.C that does the following:
   1. Prompt the user for a filename using cout.
   2. Input the filename into a string using cin.
   3. Open the file.
   4. Input the values from the file one by one into a float variable using >>.
   5. Store the values into a vector using push_back().
   6. Print the number of values using size().
   7. Print the values in reverse order in a column with decimal points aligned.
   8. Print each value with three (3) decimal places.
5. Compile floats.C. Do NOT use printf and/or scanf.
6. Execute the program.
7. After completing the program, have the TA verify your work so that you receive credit for today's lab.

Note

1. Make sure you #include all the files needed to correctly use streams, strings and vectors, and to format the output.
2. When asked to input a filename, type floats.dat.

Sample Output

[linux1:/afs/umbc.edu/users/a/n/aniket1/home/202/labs/lab2] ./lab2 
Enter a filename: floats.dat
Original values:
3.454
0.0032
-45.44
-1.33
-0.0004
1
89983

Number of values: 7

Values formatted in reverse order with decimal points aligned:
  89983.00
      1.00
     -0.00
     -1.33
    -45.44
      0.00
      3.45

Values formatted to 3 decimal places:
3.454
0.003
-45.440
-1.330
-0.000
1.000
89983.000
[linux1:/afs/umbc.edu/users/a/n/aniket1/home/202/labs/lab2]

Tips

1. To get the decimal points aligned in a column, set the width of the output to some value. Then set the precision as desired.

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