Skip to content

Instantly share code, notes, and snippets.

@rszewczyk

rszewczyk/cw08.c

Last active April 11, 2017 18:42
Show Gist options
  • Save rszewczyk/304f68c41e46358ee264062180e1d123 to your computer and use it in GitHub Desktop.
Save rszewczyk/304f68c41e46358ee264062180e1d123 to your computer and use it in GitHub Desktop.
Download ZIP
UMBC CMSC104 Classwork 8
Raw
cw08.c
#include <stdio.h>
/*
* Basics of a while loop
*/
int main() {
/*
* Part 1 Instructions
*
* There is nothing to change here. Just read
* the instructions, compile the program, and
* observe the output for this section. Make
* sure you understand how the while loop works
* before proceeding.
*
* Loops are used to repeat a section of code.
* The first type of loop we will use in this
* class is the while loop. A complete while loop
* has three parts.
* 1. The keyword "while"
* 2. A conditional expression (an expression
* that is either true or false).
* 3. The loop body. This section of code will
* will repeat so long as the conditional is
* true. The conditional is re-evaluated on
* every execution (iteration) of the loop.
*/
printf("Start part 1\n");
int number_1 = 0;
/* To start the while loop, use the keyword "while"
* followed by the conditional expression in
* parenthesis. In order for the loop to execute at least
* one time, the conditional has to be true the first
* time it is evaluated. Note that to satisfy this
* requirement the variable "number_1" is initialized to 0
* - since (0 < 10) is true when the program first reaches
* the loop.
*/
while (number_1 < 10)
{
/*
* The loop body is this section of code between the
* braces. It will be executed if the conditional
* is true. After the body is executed the conditional
* is checked again and if it is still true, the body
* is executed again. This continues until the
* conditional is false.
*/
printf("%d\n", number_1);
/*
* Note that since we increment the value by one each time,
* the conditional will be different each time (1 < 10,
* 2 < 10, 3 < 10, 4 < 10, etc). This will eventually be false.
* In general, a loop will always need some kind of terminating
* conditional like this. Otherwise, the loop will execute forever.
*/
number_1 = number_1 + 1;
}
printf("End part 1\n\n\n");
/*
* Part 2 Instructions
*
* Write a while loop that prints the first 10 numbers starting with 10
* counting back by 1 (10, 9, 8, etc). Print each number on its own line.
*/
printf("Start part2\n");
// Your code for Part 2 goes here.
printf("End part 2\n\n\n");
/*
* Part 3 Instructions
*
* There is nothing to change here. This is another
* example of a simple while loop.
*/
printf("Start part3\n");
int number_3 = 0;
int sum_3 = 0;
while (number_3 < 10)
{
sum_3 = sum_3 + number_3;
number_3 = number_3 + 1;
}
printf("The sum of of the first 10 non negative integers is %d\n", sum_3);
printf("End part 3\n\n\n");
/*
* Part 4 Instructions
*
* Write a while loop that prints the sum of the first 10 even numbers.
*/
printf("Start part4\n");
// Your code for part 4 goes here
printf("End part 4\n\n\n");
/*
* Part 5 Instructions
*
* There is nothing to change here. This example demonstrates
* local variables within a loop body
*
* Recall that a set of braces defines a scope - any variables
* defined within a scope exist only in that scope. Furthermore
* a loop body represents a different scope per execution. In
* other words variables declared within the loop body are not
* shared between iterations.
*/
printf("Start part5\n");
int number_5 = 0;
while (number_5 < 10) {
/*
* This declaration and initialization happens every time
* the loop executes - i.e. oneLess represents a new variable
* every time the loop body is executed.
*/
int oneLess = number_5 - 1;
printf("%d\n", oneLess);
number_5 = number_5 + 1;
/*
* since oneLess is declared within the loop body, it is
* discarded at the end of each of the loop body on each
* iteration
*/
}
// oneLess doesn't exist outside the loop body
printf("End part 5\n\n\n");
/*
* Part 6 Instructions
*
* The code in this sections has one or more
* bugs. Fix the code so that it correctly
* calculates and prints the result of 5!
*/
printf("Start part6\n");
int number_6 = 5;
int factorial_6 = 1;
while (number_6 > 1) {
int factorial_6 = factorial_6 * number_6;
number_6 = number_6 - 1;
}
printf("5 factorial is %d\n", factorial_6);
printf("End part 6\n\n\n");
/*
* Part 7 Instructions
*
* When you get to this section delete the two
* lines that say "DELETE THIS LINE" (make sure you
* delete everything on the line).
*
* Compile and run the program but try to read and
* understand what it is doing first.
*
* There is nothing else to change here. This example
* demonstrates using a loop to get valid input from
* a user.
*/
printf("Start part 7\n");
/* DELETE THIS LINE
// this variable both controls the loop and holds
// input from the user. We set it to an invalid
// value at first so that the loop will execute.
int number_7 = 1;
while (number_7 % 2 != 0) {
// repeatedly ask for input until the user enters it
// correctly
printf("Type an even number and press enter: ");
scanf("%d", &number_7);
if (number_7 % 2 != 0) {
// be sure you let the user know what is wrong
// with the input.
printf("%d is not even. ", number_7);
}
}
printf("Congrats you got it right.\n");
DELETE THIS LINE */
printf("End part 7\n\n\n");
/*
* Part 8 Instructions
*
* Write the code to get two numbers from the user -
* a floating point numerator and floating point denominator.
* Print the result of dividing the numerator by the
* denominator. The code should not allow the user to enter
* 0 for the denominator.
*
*/
printf("Start part8\n");
// your code for part 8 goes here
printf("End part 8\n\n\n");
/*
* Part 9 Instructions
*
* Loops can be nested inside other loops. After you have
* reviewed and understand the code below, modify it so that
* each row prints the number of starts equal to successive odd
* numbers starting with 1 (the first row prints 1 star,
* the second row prints 3 stars, the third row prints 5 stars, etc )
*/
// printf("Start part9\n");
int numberRows = 0;
// the outer loops controls the number of rows
while (numberRows < 10) {
int numberStars = 0;
/*
* The inner loop controls the number of stars in a row.
* this loop is executed once per execution of the outer
* loop body. This means the inner loops body will run
* a total of 10 x 20 times. Also note that since the
* assignment of the numberStars variable happens at the
* beginning of the outer loops body, it "resets" the
* inner loop each time the outer loop body executes.
*/
while (numberStars < 20) {
printf("*");
numberStars = numberStars + 1;
}
printf("\n");
numberRows = numberRows + 1;
}
printf("End part 9\n\n");
return 0;
}
Raw
instructions.md

Classwork 8

Step 1.

Download the source code for classwork 7 using the following command:

curl -L https://goo.gl/echu6S > cw08.c

Alternatively, you can copy and paste the contents into a file you created named cw08.c.

Step 2.

Compile and run the program to make sure everything downloaded ok.

Step 3.

Open the file in your preferred editor and follow the instruction for each part (there are 8 parts total). Note that not all of the parts require you to make changes to the source code - but you should still read those parts because the next part typically asks you to implement something similar.

Step 4.

Submit the assignment

submit cs104_kdruffel cw08 cw08.c

Hint #1

You're starting off with a program that successfully compiles. As you work on it, it's a good idea to make only small changes at a time and attempt to recompile. That way if something breaks, you have a good idea of what change triggered the error (in addition to the information the compiler prints out).

Hint #2

Since you're working with loops, you might encounter a situation where your program gets into an infinite loops (it runs continuously without stopping). If that happens, stop your program by holding the control key and pressing c.

Raw
solution.c
#include <stdio.h>
/*
* Basics of a while loop
*/
int main() {
/*
* Part 1 Instructions
*
* There is nothing to change here. Just read
* the instructions, compile the program, and
* observe the output for this section. Make
* sure you understand how the while loop works
* before proceeding.
*
* Loops are used to repeat a section of code.
* The first type of loop we will use in this
* class is the while loop. A complete while loop
* has three parts.
* 1. The keyword "while"
* 2. A conditional expression (an expression
* that is either true or false).
* 3. The loop body. This section of code will
* will repeat so long as the conditional is
* true. The conditional is re-evaluated on
* every execution (iteration) of the loop.
*/
printf("Start part 1\n");
int number_1 = 0;
/* To start the while loop, use the keyword "while"
* followed by the conditional expression in
* parenthesis. In order for the loop to execute at least
* one time, the conditional has to be true the first
* time it is evaluated. Note that to satisfy this
* requirement the variable "number_1" is initialized to 0
* - since (0 < 10) is true when the program first reaches
* the loop.
*/
while (number_1 < 10)
{
/*
* The loop body is this section of code between the
* braces. It will be executed if the conditional
* is true. After the body is executed the conditional
* is checked again and if it is still true, the body
* is executed again. This continues until the
* conditional is false.
*/
printf("%d\n", number_1);
/*
* Note that since we increment the value by one each time,
* the conditional will be different each time (1 < 10,
* 2 < 10, 3 < 10, 4 < 10, etc). This will eventually be false.
* In general, a loop will always need some kind of terminating
* conditional like this. Otherwise, the loop will execute forever.
*/
number_1 = number_1 + 1;
}
printf("End part 1\n\n\n");
/*
* Part 2 Instructions
*
* Write a while loop that prints the first 10 numbers starting with 10
* counting back by 1 (10, 9, 8, etc). Print each number on its own line.
*/
printf("Start part2\n");
int number_2 = 10;
while (number_2 > 0) {
printf("%d\n", number_2);
number_2 = number_2 - 1;
}
printf("End part 2\n\n\n");
/*
* Part 3 Instructions
*
* There is nothing to change here. This is another
* example of a simple while loop.
*/
printf("Start part3\n");
int number_3 = 0;
int sum_3 = 0;
while (number_3 < 10)
{
sum_3 = sum_3 + number_3;
number_3 = number_3 + 1;
}
printf("The sum of of the first 10 non negative integers is %d\n", sum_3);
printf("End part 3\n\n\n");
/*
* Part 4 Instructions
*
* Write a while loop that prints the sum of the first 10 even numbers.
*/
printf("Start part4\n");
int number_4 = 0;
int sum_4 = 0;
while (number_4 < 20)
{
if (number_4 % 2 == 0) {
sum_4 = sum_4 + number_4;
}
number_4 = number_4 + 1;
}
printf("The sum of of the first 10 non negative even integers is %d\n", sum_4);
printf("End part 4\n\n\n");
/*
* Part 5 Instructions
*
* There is nothing to change here. This example demonstrates
* local variables within a loop body
*
* Recall that a set of braces defines a scope - any variables
* defined within a scope exist only in that scope. Furthermore
* a loop body represents a different scope per execution. In
* other words variables declared within the loop body are not
* shared between iterations.
*/
printf("Start part5\n");
int number_5 = 0;
while (number_5 < 10) {
/*
* This declaration and initialization happens every time
* the loop executes - i.e. oneLess represents a new variable
* every time the loop body is executed.
*/
int oneLess = number_5 - 1;
printf("%d\n", oneLess);
number_5 = number_5 + 1;
/*
* since oneLess is declared within the loop body, it is
* discarded at the end of each of the loop body on each
* iteration
*/
}
// oneLess doesn't exist outside the loop body
printf("End part 5\n\n\n");
/*
* Part 6 Instructions
*
* The code in this sections has one or more
* bugs. Fix the code so that it correctly
* calculates and prints the result of 5!
*/
printf("Start part6\n");
int number_6 = 5;
int factorial_6 = 1;
while (number_6 > 0) {
factorial_6 = factorial_6 * number_6;
number_6 = number_6 - 1;
}
printf("5 factorial is %d\n", factorial_6);
printf("End part 6\n\n\n");
/*
* Part 7 Instructions
*
* When you get to this section delete the two
* lines that say "DELETE THIS LINE" (make sure you
* delete everything on the line).
*
* Compile and run the program but try to read and
* understand what it is doing first.
*
* There is nothing else to change here. This example
* demonstrates using a loop to get valid input from
* a user.
*/
printf("Start part 7\n");
// this variable both controls the loop and holds
// input from the user. We set it to an invalid
// value at first so that the loop will execute.
int number_7 = 1;
while (number_7 % 2 != 0) {
// repeatedly ask for input until the user enters it
// correctly
printf("Type an even number and press enter: ");
scanf("%d", &number_7);
if (number_7 % 2 != 0) {
// be sure you let the user know what is wrong
// with the input.
printf("%d is not even. ", number_7);
}
}
printf("Congrats you got it right.\n");
printf("End part 7\n\n\n");
/*
* Part 8 Instructions
*
* Write the code to get two numbers from the user -
* a floating point numerator and floating point denominator.
* Print the result of dividing the numerator by the
* denominator. The code should not allow the user to enter
* 0 for the denominator.
*
*/
printf("Start part8\n");
float numerator;
float denominator = 0;
printf("Enter the numerator: ");
scanf("%f", &numerator);
while (denominator == 0) {
printf("Enter the denominator: ");
scanf("%f", &denominator);
if (denominator == 0) {
printf("The denominator cannot be zero. ");
}
}
printf("%f divided by %f is %f\n", numerator, denominator, numerator / denominator);
printf("End part 8\n\n\n");
/*
* Part 9 Instructions
*
* Loops can be nested inside other loops. After you have
* reviewed and understand the code below, modify it so that
* each row prints the number of starts equal to successive odd
* numbers starting with 1 (the first row prints 1 star,
* the second row prints 3 stars, the third row prints 5 stars, etc )
*/
// printf("Start part9\n");
int numberRows = 0;
int starCount = 1;
// the outer loops controls the number of rows
while (numberRows < 10) {
int numberStars = 0;
/*
* The inner loop controls the number of stars in a row.
* this loop is executed once per execution of the outer
* loop body. This means the inner loops body will run
* a total of 10 x 20 times. Also note that since the
* assignment of the numberStars variable happens at the
* beginning of the outer loops body, it "resets" the
* inner loop each time the outer loop body executes.
*/
while (numberStars < starCount) {
printf("*");
numberStars = numberStars + 1;
}
printf("\n");
numberRows = numberRows + 1;
starCount = starCount + 2;
}
printf("End part 9\n\n");
return 0;
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment