#include <iostream>
#include <string>
using namespace std;
void bubbleSort(int data[], int n);
int main()
{
cout << "Enter ten unsorted integers..." << endl;
int a[10];
for (int i = 0; i < 10; ++ i)
{
cout << "[" << i << "] = ";
cin >> a[i];
}
cout << endl << "Unsorted List = ";
for (int i = 0; i < 10; ++i)
cout << a[i] << ", ";
cout << endl;
cout << "Sorting..." << endl;
cout << "Sorted List = ";
bubbleSort(a, 10);
}
void bubbleSort(int data[], int n)
{
int j = 0;
bool nextEnd = true;
while (nextEnd)
{
nextEnd = false;
++j;
for (int i = 0; i < n - j; ++i)
{
if (data[i] > data[i+1])
{
int temp = data[i];
data[i] = data[i+1];
data[i+1] = data[i];
nextEnd = true;
}
}
}
for (int i = 0; i < 10; ++i)
cout << data[i] << ", ";
}
The program is really simple. Input ten values to an array. Display them unsorted. Send them into the bubbleSort function, sort them and finally display the sorted list. The problem I'm having is I don't get the outputting back to work. I tested with the last line of code but that doesn't work. I don't think my sorting is messed up either. How can I display this sorted list properly?
There is at least one error in the bubble sort. The assignment to data[i+1] is not correct. It should be:
data[i+1] = temp;
The problem is your 'swap'. It should be:
int temp = data[i];
data[i] = data[i+1];
data[i+1] = temp;
Edit-Tested and works fine with the correction.
Related
I'm a C++ newb. I need to insert numbers to an array and then display first the odd numbers and then the even numbers in a single array. I've managed to create two separate arrays with the odd and even numbers but now I don't know how to sort them and put them back in a single array. I need your help to understand how to do this with basic C++ knowledge, so no advanced functions. Here's my code:
#include <iostream>
using namespace std;
int main()
{
int N{ 0 }, vector[100], even[100], odd[100], unify[100], i{ 0 }, j{ 0 }, k{ 0 };
cout << "Add the dimension: " << endl;
cin >> N;
cout << "Add the elements: " << endl;
for (int i = 0; i < N; i++) {
cout << "v[" << i << "]=" << endl;
cin >> vector[i];
}
for (i = 0; i < N; i++) {
if (vector[i] % 2 == 0) {
even[j] = vector[i];
j++;
}
else if (vector[i] % 2 != 0) {
odd[k] = vector[i];
k++;
}
}
cout << "even elements are :" << endl;
for (i = 0; i < j; i++) {
cout << " " << even[i] << " ";
cout << endl;
}
cout << "Odd elements are :" << endl;
for (i = 0; i < k; i++) {
cout << " " << odd[i] << " ";
cout << endl;
}
return 0;
}
If you don't need to store the values then you can simply run through the elements and print the odd and the even values to different stringstreams, then print the streams at the end:
#include <sstream>
#include <stddef.h>
#include <iostream>
int main () {
std::stringstream oddStr;
std::stringstream evenStr;
static constexpr size_t vecSize{100};
int vec[vecSize] = {10, 5, 7, /*other elements...*/ };
for(size_t vecIndex = 0; vecIndex < vecSize; ++vecIndex) {
if(vec[vecIndex] % 2 == 0) {
evenStr << vec[vecIndex] << " ";
} else {
oddStr << vec[vecIndex] << " ";
}
}
std::cout << "Even elements are:" << evenStr.rdbuf() << std::endl;
std::cout << "Odd elements are:" << oddStr.rdbuf() << std::endl;
}
Storing and sorting the elements are always expensive.
Basically, it would be better to sort them first.
#include <iostream>
using namespace std;
int main()
{
int numbers[5];
int mergedArrays[5];
int evenNumbers[5];
int oddNumbers[5];
for(int i=0;i<5;i++){
cin>>numbers[i];
}
int temp=numbers[0];
//bubble sort
for(int i = 0; i<5; i++)
{
for(int j = i+1; j<5; j++)
{
if(numbers[j] < numbers[i])
{
temp = numbers[i];
numbers[i] = numbers[j];
numbers[j] = temp;
}
}
}
int nEvens=0;
int nOdds=0;
for(int i = 0; i<5; i++)
{
if(numbers[i]%2==0)
{
evenNumbers[nEvens]=numbers[i];
nEvens++;
}
else if(numbers[i]%2!=0)
{
oddNumbers[nOdds]=numbers[i];
nOdds++;
}
}
int lastIndex=0;
//copy evens
for(int i = 0; i<nEvens; i++)
{
mergedArrays[i]=evenNumbers[i];
lastIndex=i;
}
//copy odds
for(int i =lastIndex; i<nOdds; i++)
{
mergedArrays[i]=oddNumbers[i];
}
return 0;
}
If you have to just output the numbers in any order, or the order given in the input then just loop over the array twice and output first the even and then the odd numbers.
If you have to output the numbers in order than there is no way around sorting them. And then you can include the even/odd test in the comparison:
std::ranges::sort(vector, [](const int &lhs, const int &rhs) {
return ((lhs % 2) < (rhs % 2)) || (lhs < rhs); });
or using a projection:
std::ranges::sort(vector, {}, [](const int &x) {
return std::pair<bool, int>{x % 2 == 0, x}; });
If you can't use std::ranges::sort then implementing your own sort is left to the reader.
I managed to find the following solution. Thanks you all for your help.
#include <iostream>
using namespace std;
int main()
{
int N{0}, vector[100], even[100], odd[100], merge[100], i{0}, j{0}, k{0}, l{0};
cout << "Add the dimension: " << endl;
cin >> N;
cout << "Add the elements: " << endl;
for (int i = 0; i < N; i++)
{
cout << "v[" << i << "]=" << endl;
cin >> vector[i];
}
for (i = 0; i < N; i++)
{
if (vector[i] % 2 == 0)
{
even[j] = vector[i];
j++;
}
else if (vector[i] % 2 != 0)
{
odd[k] = vector[i];
k++;
}
}
cout << "even elements are :" << endl;
for (i = 0; i < j; i++)
{
cout << " " << even[i] << " ";
cout << endl;
}
cout << "Odd elements are :" << endl;
for (i = 0; i < k; i++)
{
cout << " " << odd[i] << " ";
cout << endl;
}
for (i = 0; i < k; i++)
{
merge[i] = odd[i];
}
for (int; i < j + k; i++)
{
merge[i] = even[i - k];
}
for (int i = 0; i < N; i++)
{
cout << merge[i] << endl;
}
return 0;
}
You can use Bubble Sort Algorithm to sort whole input. After sorting them using if and put odd or even numbers in start of result array and and others after them. like below:
//Bubble Sort
void bubbleSort(int arr[], int n)
{
int i, j;
for (i = 0; i < n - 1; i++)
// Last i elements are already
// in place
for (j = 0; j < n - i - 1; j++)
if (arr[j] > arr[j + 1])
swap(arr[j], arr[j + 1]);
}
// Insert In array
int result[100];
if(odd[0]<even[0])
{
for (int i = 0; i < k; i++)
{result[i] = odd[i];}
for (int i = 0; i < j; i++)
{result[i+k] = even[i];}
}else
{
for (int i = 0; i < j; i++)
{result[i] = even[i];}
for (int i = 0; i < k; i++)
{result[i+k] = odd[i];}
}
I need to write a C++ program where it swaps between two 1-dimensional
arrays using pointers and functions. Firstly, a void function named showValues to display both arrays before swapping takes and also a void function named swap to swap the elements between both arrays.
My question is: I'm supposed to swap the function but for some reason it wont run and I am not sure where is the error in my code
#include <iostream>
#include <iomanip>
using namespace std;
const int SIZE = 5;
void showValues(int[],int[]);
void swap(int[],int[]);
int main() {
int array1[SIZE] = {10,20,30,40,50};
int array2[SIZE] = {60,70,80,90,100};
showValues (array1, array2);
swap(array1, array2);
return 0;
}
void showValues(int array1[], int array2[]){
cout<<"The original arrays are as shown below: " << endl;
cout << " Array 1 is: ";
for (int i = 0; i < 5; ++i) {
cout << array1[i] << " ";
}
cout << "\n Array 2 is: ";
for (int i = 0; i < 5; ++i) {
cout << array2[i] << " ";
}
}
void swap(int array1[], int array2[])
{
int temp,i;
for(i=0; i<5; ++i)
{
temp = array1[SIZE];
array1[SIZE] = array2[SIZE];
array2[SIZE] = temp;
}
cout << "\nThe swapped arrays are as shown below: " << endl;
cout << " Array 1 is: ";
for (int i = 0; i < 5; ++i) {
cout << array1[i] << " ";
}
cout << "\n Array 2 is: ";
for (int i = 0; i < 5; ++i) {
cout << array2[i] << " ";
}
}
This part of your code doesn't make sense:
temp = array1[SIZE];
array1[SIZE] = array2[SIZE];
array2[SIZE] = temp;
SIZE is 5. So, you are accessing array1[5] and array2[5], i.e. the 6th element of the array. Yet, your arrays have only 5 elements to begin with (array1[0] to array1[4], same for array2), so you are accessing elements beyond the end of the array, which is undefined behavior that is probably just corrupting memory somewhere!
You probably meant to use i here, not SIZE, then the code makes sense. Instead, it would be useful to replace the "magic number" 5 with SIZE:
for(i = 0; i < SIZE; ++i)
{
temp = array1[i];
array1[i] = array2[i];
array2[i] = temp;
}
The void swap(int array1[], int array2[]) function is where you are having trouble. You actually don't even need to have another function for the swapping. You could just use std::swap() which is defined in the #include <utility> header. Since both arrays have the same size.
For example you could do something along these lines:
#include <iostream>
#include <iomanip>
#include <utility>
const int SIZE = 5;
void showValues(int[], int[]);
void swap(int[], int[]);
int main() {
int array1[SIZE] = { 10,20,30,40,50 };
int array2[SIZE] = { 60,70,80,90,100 };
int n = sizeof(array1) / sizeof(array2[0]);
showValues(array1, array2);
std::swap(array1, array2);
std::cout << "\n\nThe swapped arrays are as shown below:\n ";
std::cout << "\nArray 1 is: ";
for (int i = 0; i < n; i++)
std::cout << array1[i] << ", ";
std::cout << "\nArray 2 is: ";
for (int i = 0; i < n; i++)
std::cout << array2[i] << ", ";
return 0;
}
void showValues(int array1[], int array2[]) {
std::cout << "The original arrays are as shown below: " << std::endl;
std::cout << "\nArray 1 is: ";
for (int i = 0; i < 5; ++i) {
std::cout << array1[i] << " ";
}
std::cout << "\nArray 2 is: ";
for (int i = 0; i < 5; ++i) {
std::cout << array2[i] << " ";
}
}
Also consider not using using namespace std;.
In the code below, I am trying to output the integers in ascending order. It works, however I want the final integer to be put on a newline (final integer only- not the other integers). I have tried
cout << myVec[i] << " "; endl
and...
cout << myVec[i] << endl;
but, both do not give the output I am looking for (these affect the other integers which is not what I want.
#include <iostream>
#include <vector>
using namespace std;
void SortVector(vector<int>& myVec)
{
int n = myVec.size();
int i, j;
for (i = 0; i < n - 1; i++)
for (j = 0; j < n - i - 1; j++)
if (myVec[j] > myVec[j + 1])
{
int temp = myVec[j];
myVec[j] = myVec[j + 1];
myVec[j + 1] = temp;
}
}
int main()
{
int i, n, value;
cin >> n;
vector<int> myVec;
for (i = 0; i < n; i++)
{
cin >> value;
myVec.push_back(value);
}
SortVector(myVec);
for (i = 0; i < n; i++)
cout << myVec[i] << " ";
return 0;
}
Print all but the last element on one line:
for (i = 0; i < n-1; i++) // notice n-1
std::cout << myVec[i] << ' ';
std::cout << '\n';
Then you can print the last afterwards:
if(myVec.size())
std::cout << myVec.back() << '\n';
For this vectors and merging assignment, we are supposed to read in user inputted strings and sort them alphabetically. I got the first two parts, but when I am putting the sorted elements in the new vector, it says that my new vector is out of range. Does anyone know how to fix this?
#include <iostream>
#include <vector>
using namespace std;
int main() {
vector<string> que1;
vector<string> que2;
vector<string> que_merge;
string firstName;
string secondName;
int counterq1 = 0;
int counterq2 = 0;
cout << "Enter queues: " << endl;
bool check = true;
while(check) {
cin >> firstName;
if (firstName == "ENDQ"){
check = false;
}
else{
que1.push_back(firstName);
counterq1++;
check = true;
}
}
// que1.resize(counterq1);
bool check2 = true;
while (check2) {
cin >> secondName;
if (secondName == "ENDQ") {
check2 = false;
} else {
que2.push_back(secondName);
counterq2++;
}
}
// que2.resize(counterq2);
cout << "que1: " << counterq1 << endl;
for (int i = 0; i < que1.size(); i++) {
cout << que1.at(i) << endl;
}
cout << endl;
cout << "que2: " << counterq2 << endl;
for (int j = 0; j < que2.size(); j++) {
cout << que2.at(j) << endl;
}
cout << endl;
cout << "que_merge: " << counterq1 + counterq2 << endl;
int i = 0;
int k = 0;
int j = 0;
while (1){
if (i >= counterq1 || j >= counterq2){
break;
}
if(que1.at(i) < que2.at(j)){
que_merge.push_back(que1.at(i));
i++;
}
else{
que_merge.push_back(que2.at(j));
j++;
}
k++;
}
if (que1.empty()){
for (int m = j; m < counterq2; m++){
que_merge.push_back(que2.at(m));
}
} else {
for (int l = i; l < counterq1; ++l) {
que_merge.push_back(que1.at(l));
}
}
for (int l = 0; l < (counterq1+counterq2); l++) {
cout << que_merge.at(l) << endl;
}
return 0;
}
I think your problem is that these lines:
if (que1.empty()){
for (int m = j; m < counterq2; m++){
que_merge.push_back(que2.at(m));
}
} else {
for (int l = i; l < counterq1; ++l) {
que_merge.push_back(que1.at(l));
}
}
doesn't do what you expect.
As far as I can see, your idea is to merge the remaining element from either que1 or que2.
However, that is not what you get from this code as the elements in que1 and que2 is never erased. In other words - the check for an empty queue is rather meaningless and you can't be sure that all elements are added to que_merge
So when you do:
for (int l = 0; l < (counterq1+counterq2); l++) {
cout << que_merge.at(l) << endl;
}
you may read beyond the number of elements in que_merge
Tip:
Don't count the number of elements your self. Use size() (like que_merge.size()) instead. For instance:
for (int l = 0; l < que_merge.size(); l++) {
cout << que_merge.at(l) << endl;
}
or a range based loop like:
for (const auto& s : que_merge) {
cout << s << endl;
}
#include <algorithm>
Use std::merge and std::sort, not necessarily in that order.
If the assignment says you can't do it the C++ way, that you have to write it all out, you can do it the engineer's way: Find an example that works, and crib it.
There are two possible implementations of std::merge on this page: All about C++ merge
This is pretty straightforward question. I checked online with the bubble sort code, and it looks like i am doing the same. Here's my complete C++ code with templates. But the output is kinda weird!
#include <iostream>
using namespace std;
template <class T>
void sort(T a[], int size){
for(int i=0; i<size; i++){
for(int j=0; j<i-1; j++){
if(a[j+1]>a[j]){
cout<<"Yes at j="<<j<<endl;
T temp = a[j];
a[j] = a[j+1];
a[j+1] = temp;
}
}
}
}
int main(){
int a[] = {1,2,6,3,4,9,8,10};
sort<int>(a,8);
for(int i = 0; i<8; i++){
cout<<a[i]<<endl;
}
return 0;
}
Output:
But when i slightly change the logic to try to sort it on ascending order. i.e., changing to : if(a[j+1]<a[j]) , The output is fine!
Where am i doing this wrong?
Thanks in advance!
The problem with your code is that you try to bubble stuff down, but loop upward. If you want to bubble stuff down, you need to loop downward so an element that needs to go down goes down as far as it needs to. Otherwise, with every iteration of i you only know that an element may be bubbled down one space.
Similarly, if you bubble things upwards, you also need to loop upwards.
If you want to see what happens, here's your code with some output statements so you can follow what's going on:
#include <iostream>
using namespace std;
template <class T>
void sort(T a[], int size){
for(int i=0; i<size; i++){
cout << "i: " << i << endl;
for(int j=0; j<i-1; j++){
if(a[j+1]>a[j]){
cout << "\t Yes at j = " << j << endl;
T temp = a[j];
a[j] = a[j+1];
a[j+1] = temp;
for(int k = 0; k < size; k++) {
cout << "\t a[" << k << "]: " << a[k] << endl;
}
cout << endl;
}
}
cout << "\n" << endl;
}
}
int main(){
int a[] = {1,2,6,3,4,9,8,10};
cout << "initially:" << endl;
for(int k = 0; k < 8; k++) {
cout << "a[" << k << "]: " << a[k] << endl;
}
cout << "\n" << endl;
sort<int>(a,8);
cout << "\n sorted:" << endl;
for(int i = 0; i<8; i++){
cout << a[i] << endl;
}
return 0;
}
If you run this, you can see that for entries with higher index, there aren't enough iterations left to bubble them down all the way to where they need to go.
Also, here's code with your bubbling-down fixed (i.e. sorting in reverse order):
#include <iostream>
using namespace std;
template <class T>
void sort(T a[], int size){
for(int i=0; i<size; i++){
cout << "i: " << i << endl;
for(int j=size - 1; j>i; j--){
if(a[j-1]<a[j]){
cout << "\t Yes at j = " << j << endl;
T temp = a[j];
a[j] = a[j-1];
a[j-1] = temp;
}
}
}
}
int main(){
int a[] = {1,2,3,4,5,6,8,10};
sort<int>(a,8);
cout << "\n sorted:" << endl;
for(int i = 0; i<8; i++){
cout << a[i] << endl;
}
return 0;
}
When using bubble sort, you need to keep in mind in which directions your "bubbles" move. You first have to pick the biggest/smallest element from all the array and move it to the end at position n-1. Then pick the next one and move it to to position n.
for (int i=size; i>1; i=i-1) { // << this is different
for (int j=0; j<i-1; j=j+1) {
if (a[j] < a[j+1]) {
std::swap(a[j], a[j+1]);
}
}
}
See here for an even better implementation.
It is a logic problem:
for(int i = 0; i < size; i++){
for(int j = 0; j < (i); j++){
if(a[i] > a[j]){
cout<<"Yes at j="<<j<<endl;
T temp = a[j];
a[j] = a[i];
a[i] = temp;
}
}
}
You should change the a[j+1] for a[i]
You are comparing and swapping wrong numbers, look for differences here:
template <class T>
void sort(T a[], int size){
for(int i = 0; i < size; i++){
for(int j = i+1; j < size; j++){
if(a[i] < a[j]){
cout << "Yes at j=" << j << endl;
//swap(a[j], a[j+1]);
T temp = a[j];
a[j] = a[i];
a[i] = temp;
}
}
}
}