C++ Datastructures and Algorithms Final Exam Solutions

1. Assume the following variable declarations:

int foo = 0;
int *ptr = &foo;

What statements will change the value of foo to 1?

(*ptr)++;
foo++;

2. Write a function countMatches which compares 2 C strings and count the number of matching characters.

void countMatches(const char *str1, const char *str2, int &count) { 
int count = 0;
while (*str1 != '\0' &&*str2 != '\0') { 
if (*str1 == *str2) {
count++;
} 
str1++;
str2++;
} 
}

3. Design the class Goldfish, which models a creature that is intelligent enough to remember capacity characters at a time.

(a) Define the constructor

Goldfish(int capacity) {
if (capacity < 0){
m_capacity = 3;
} else if (capacity > 10){
m_capacity = 10;
}
m_amount = 0;
forget();
}

(b) Implement remember. Store the character c into m_memory. If you already have m_capacity characters memorized, then discard the oldest character in m_memory to open up a free slot. (This is an example of LRU (Least Recently Used) replacement.)

void Goldfish::remember(char c){
if (m_amount == m_capacity){