Week 04 Laboratory Exercises

Write a C program, print_pi.c, which prints out the first n digits of pi, where n is specified by the user.

Download print_pi.c here, or copy it to your CSE account using the following command:

cp -n /web/cs1511/21T1/activities/print_pi/print_pi.c .

You will never be given more than 10 integers to print out.

The output from your program should look exactly like this:

dcc print_pi.c -o print_pi
./print_pi
How many digits of pi would you like to print? 3
3.14
./print_pi
How many digits of pi would you like to print? 1
3
./print_pi
How many digits of pi would you like to print? 0

1511 style print_pi.c

When you think your program is working, you can use autotest to run some simple automated tests:

1511 autotest print_pi

When you are finished working on this exercise, you and your lab partner must both submit your work by running give:

give cs1511 lab04_print_pi print_pi.c

Note, even though this is a pair exercise, you both must run give from your own account before Monday 15 March 20:00 to obtain the marks for this lab exercise.

Download circle_facts.c here, or copy it to your CSE account using the following command:

cp -n /web/cs1511/21T1/activities/circle_facts/circle_facts.c .

Your task is to add code to these functions in circle_facts.c:

// Calculate the area of a circle, given its radius.
double area(double radius) {
    // TODO: complete this function.
    return M_PI; // TODO: change this to the correct return value.
}

// Calculate the circumference of a circle, given its radius.
double circumference(double radius) {
    // TODO: complete this function.
    return M_PI; // TODO: change this to the correct return value.
}

// Calculate the diameter of a circle, given its radius.
double diameter(double radius) {
    // TODO: complete this function.
    return M_PI; // TODO: change this to the correct return value.
}

Its main function is complete. Do not change the main function. Complete these three functions:

double area(double radius);
double circumference(double radius);
double diameter(double radius);

Hint use the constant M_PI defined in math.h

dcc -o circle_facts  circle_facts.c 
./circle_facts 
Enter circle radius: 1
Area          = 3.141593
Circumference = 6.283185
Diameter      = 2.000000
./circle_facts
Enter circle radius: 17
Area          = 907.920277
Circumference = 106.814150
Diameter      = 34.000000
./circle_facts
Enter circle radius: 0.0125
Area          = 0.000491
Circumference = 0.078540
Diameter      = 0.025000

1511 style circle_facts.c

When you think your program is working, you can use autotest to run some simple automated tests:

1511 autotest circle_facts

When you are finished working on this exercise, you and your lab partner must both submit your work by running give:

give cs1511 lab04_circle_facts circle_facts.c

Note, even though this is a pair exercise, you both must run give from your own account before Monday 15 March 20:00 to obtain the marks for this lab exercise.

For this exercise, make a program called painterbot.c which will scan in indices until EOF and then print out a one dimensional array which has 36 '0's, except at the given indices it has a '1'.

You can assume that every number you are given will be between 0 and 35. You can assume you will never get the same number twice.

./painterbot
5
2
4

0 0 1 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

./painterbot
0
1
2
3
4
5
6
7
8
9

1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

int scanned_in_value;
int result = scanf("%d", &scanned_in_value);

1511 style painterbot.c

When you think your program is working, you can use autotest to run some simple automated tests:

1511 autotest painterbot

When you are finished working on this exercise, you and your lab partner must both submit your work by running give:

give cs1511 lab04_painterbot painterbot.c

Note, even though this is a pair exercise, you both must run give from your own account before Monday 15 March 20:00 to obtain the marks for this lab exercise.

For this exercise, make a program called cs_calculator.c which will scan in instructions until EOF and prints the output as specified below. An instruction is a sequence of positive integers. The first integer identifies what type the instruction is.

• If the first number in the instruction is 1, then your program should print out the square of the next number in the instruction.
• If the first number in the instruction is 2, then your program should print out the value of the next number raised to the power of the number after next.

You can assume that the first number in the instruction is only either 1 or 2

You can assume that for each instruction, the correct number of successive positive integers will be given.

./cs_calculator
Enter instruction: 1 2
4
Enter instruction: 2 5 3
125
Enter instruction: 1 4
16
Enter instruction: 2 3 4
81
Enter instruction: 

./cs_calculator
Enter instruction: 2 3 3
27
Enter instruction: 1 10
100
Enter instruction: 

Note: The autotest for this exercise expects your program to end WITHOUT a new line character when the user presses Ctrl+D. This means that the command prompt for the next command should be on the same line as the end of your program.

One major challenge of this exercise is figuring out how to use scanf effectively. The lessons you learn in this exercise regarding scanf will be useful in the first assignment.

Hint: You can scan in the first number initially, and based on the value of that first number then scan in the correct number of additional numbers.

Hint: scanf will jump over and ignore any whitespace characters including newline characters. Be careful not to overrun or underrun your input.

There is no need to print a newline character after the user presses Ctrl+D

1511 style cs_calculator.c

When you think your program is working, you can use autotest to run some simple automated tests:

1511 autotest cs_calculator

When you are finished working on this exercise, you and your lab partner must both submit your work by running give:

give cs1511 lab04_cs_calculator cs_calculator.c

Note, even though this is a pair exercise, you both must run give from your own account before Monday 15 March 20:00 to obtain the marks for this lab exercise.