78 lines
2.0 KiB
Markdown
78 lines
2.0 KiB
Markdown
> 1. The following function, which computes the area of a triangle, contains two errors. Locate the errors and show how to fix them. (*Hint*: There are no errors in the formula)
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```c
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double triangle_area(double base, height)
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double product;
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{
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product = base * height;
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return product / 2;
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}
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```
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Answer:
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```c
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// A type annotation is needed for `height`
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double triangle_area(double base, double height)
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{
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// The `product` variable declaration was not in the function block.
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double product;
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product = base * height;
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return product / 2;
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}
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```
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> 2. Write a function `check(x, y, n)` that returns `1` if both `x` and `y` fall between zero and `n - 1` inclusive. The function should return 0 otherwise. Assume that `x`, `y`, and `n` are all of type int
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```c
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int check(int x, int y, int n) {
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int in_range = 1;
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if (x < 0 || y < 0) {
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in_range = 0;
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}
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if (x > n - 1 || y > n - 1) {
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in_range = 0;
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}
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return in_range;
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}
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```
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> 7. Suppose that function `f` has the following definition:
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> `int f(int a, int b) { ... }`
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> Which of the following statements are legal? Assume that `i` has type `int` and `x` has type `double`).
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Answer:
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All of them are legal and will compile and run. (c) and (d) are what I would consider bad practice because they perform an implicit conversion from a double to an int, and should include an explicit cast.
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> 8. Which of the following would be valid prototypes for a function that returns nothing and has one double parameter?
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Answer:
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(a) and (b).
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Parameters must contain a type annotation but they do not need to specify a name. A function prototype declaration must specify a return type.
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> 9. What will be the output of the following program?
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```c
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#include <stdio.h>
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void swap (int a, int b);
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int main(void)
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{
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int i = 1, j = 2;
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swap(i, j);
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printf("i = %d, j = %d\n", i, j);
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return 0;
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}
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void swap(int a, int b)
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{
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int temp = a;
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a = b;
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b = temp;
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}
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```
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Answer:
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```
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i = 1, j = 2
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```
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Because function parameters are passed by value and not reference in C, modifications to `a` and `b` are limited to the scope of `swap`. |