Sample MT2 (Codio) Solutions
new_cstr problem solution
#include <iostream>
#include <algorithm>
//********************
// You may NOT add other #includes
// You have to write other desired
// functionality yourself
//********************
using namespace std;
// Complete the following function
//
// This function should return a **new**, correctly-formatted C-String
// with size "length" (given by the input argument) and
// containing the substring from str[startPos] to str[startPos+length-1].
//
// str is a valid C-string. It should not be altered
// startPos starting index/position of the desired substring
// length is the desired length of the substring
//
// Return the pointer (start address) of the new array containing
// the substring. You should always return a pointer to a valid
// C-string even if the input arguments are invalid...see examples
// below.
//
// ** You may NOT use any library functions in your implementation **
//
// Example 1: csubstr("Hello world", 3, 4) should return "lo w"
// Example 2: csubstr("USC", 0, 2) should return "US"
//
// if any part of the specified range of the substring falls out of
// bounds of the input string, return a substring containing only
// the valid portion.
//
// Example 3: csubstr("USC", 1, 10) should return just "SC"
// since the length is beyond the end of "USC"
//
//
char* new_csubstr(char* str, int startPos, int length)
{
int mylen=0;
while(str[mylen] != '\0') mylen++;
// we might waste some memory if `length` characters
// cannot be extracted, but let's use the length given us
char* retval = new char[length+1];
int oidx = 0;
int maxIndex = min(startPos+length, mylen);
for(int i=startPos; i < maxIndex; i++){
retval[oidx] = str[i];
oidx++;
}
retval[oidx] = '\0';
return retval;
}
//**************************************
// Do not change these 2 lines and don't
// add any lines between them and main()
//**************************************
#ifndef AUTO_TEST
#define AUTO_TEST
int main(int argc, char* argv[])
{
//*********************************************************
// Make test calls to your function here
//*********************************************************
char* result;
result = new_csubstr("Hello world", 3, 4);
cout << result << endl;
delete [] result;
result = new_csubstr("USC", 0, 2);
cout << result << endl;
delete [] result;
return 0;
}
//****************************************
// Do not change the following line
//****************************************
#endif
election.cpp solutions
#include <iostream>
#include <fstream>
#include <iomanip>
#include <cstring>
using namespace std;
// Stores a state's name and how many
// electoral votes that state has
struct StateElectoralInfo{
string state;
int elecVotes;
};
// Complete the following function
//
// This function should search/find the target state name
// in an array of StateElectoralInfo structs
// and return its index in the array
//
// state_info is an array of filled in StateElectoralInfo structs
// len is the length/size of the state_info array
// target is the state name you need to find
//
// Return the index in the state_info array
// of the element that matches the stateName string.
// Return -1 is the stateName does not appear in the array
int findIndexOfState(StateElectoralInfo state_info[], int len, string stateName)
{
for(int i=0; i < len; i++){
if(state_info[i].state == stateName){
return i;
}
}
return -1;
}
//**************************************
// Do not change these 2 lines and don't
// add any lines between them and main()
//**************************************
#ifndef AUTO_TEST
#define AUTO_TEST
int main(int argc, char* argv[])
{
//*********************************************************
// Use these declarations to store the appropriate answers.
// Our 'couts' at the bottom expect these variables to
// be set correctly by the end of your program.
//*********************************************************
int a_elec_votes=0; // Total candidate 1 electoral college votes from all states
int b_elec_votes=0; // Total candidate 2 electoral college votes from all states
if(argc < 3){
cout << "Not enough command line arguments." << endl;
cout << "Usage: ./election <electoral college data file> <voting data file>" << endl;
return -1;
}
const string elecFileErrorMsg = "Electoral college file not found.";
const string voterFileErrorMsg = "Voter totals file not found.";
//*********************************************************
// Add your own variable declarations and write your code
// below.
//*********************************************************
ifstream ec(argv[1]);
if(ec.fail())
{
cout << elecFileErrorMsg << endl;
return -1;
}
ifstream votes(argv[2]);
if(votes.fail())
{
cout << voterFileErrorMsg << endl;
return -1;
}
StateElectoralInfo* state_info;
int numStates;
ec >> numStates;
if(ec.fail()){
cout << "Can't read the number of states" << endl;
return -1;
}
state_info = new StateElectoralInfo[numStates];
for(int i=0;i<numStates;i++)
{
ec >> state_info[i].state >> state_info[i].elecVotes;
}
int aNum, bNum;
string currState;
for(int i=0;i<numStates;i++)
{
votes >> aNum >> bNum >> currState;
int state_index = findIndexOfState(state_info, numStates, currState);
if(aNum > bNum){
a_elec_votes += state_info[state_index].elecVotes;
}
else {
b_elec_votes += state_info[state_index].elecVotes;
}
}
delete [] state_info;
//**************************************
// Output the final winner in the format:
// A (332) beats B (206)
//**************************************
if(a_elec_votes > b_elec_votes) {
cout << "A (" << a_elec_votes << ") beats B (" << b_elec_votes << ")" << endl;
}
else {
cout << "B (" << b_elec_votes << ") beats A (" << a_elec_votes << ")" << endl;
}
return 0;
}
//****************************************
// Do not change the following line
//****************************************
#endif
//****************************************
// You may add code after this if you like
//****************************************
