vault backup: 2025-01-07 18:14:44

education/computer engineering/ECE1400/Chapter 9 Exercises.md

@@ -0,0 +1,78 @@
+> 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)
+```c
+double triangle_area(double base, height)
+double product;
+{
+	product = base * height;
+	return product / 2;
+}
+```
+
+Answer:
+```c
+// A type annotation is needed for `height`
+double triangle_area(double base, double height)
+{
+	// The `product` variable declaration was not in the function block.
+	double product;
+	product = base * height;
+	return product / 2;
+}
+```
+
+> 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
+```c
+int check(int x, int y, int n) {
+	int in_range = 1;
+	if (x < 0 || y < 0) {
+		in_range = 0;
+	}
+	if (x > n - 1 || y > n - 1) {
+		in_range = 0;
+	}
+
+	return in_range;
+}
+```
+
+> 7. Suppose that function `f` has the following definition:
+> `int f(int a, int b) { ... }`
+> Which of the following statements are legal? Assume that `i` has type `int` and `x` has type `double`).
+
+Answer:
+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.
+
+> 8. Which of the following would be valid prototypes for a function that returns nothing and has one double parameter?
+
+Answer:
+(a) and (b).
+Parameters must contain a type annotation but they do not need to specify a name. A function prototype declaration must specify a return type.
+
+> 9. What will be the output of the following program?
+```c
+#include <stdio.h>
+
+void swap (int a, int b);
+
+int main(void)
+{
+    int i = 1, j = 2;
+    swap(i, j);
+    printf("i = %d, j = %d\n", i, j);
+    return 0;
+}
+
+void swap(int a, int b)
+{
+    int temp = a;
+    a = b;
+    b = temp;
+}
+
+```
+
+Answer:
+```
+i = 1, j = 2
+```
+Because function parameters are passed by value and not reference in C, modifications to `a` and `b` are limited to the scope of `swap`.