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Hello everyone, I am trying to print a reverse heart shape in c++. While user will input a integer, and the program will display the reverse heart according to the value.
in the photo, the input value are 1,3,4
Now my code can only show the triangle but still missing the two small triangle, so hoping can get some guide here.
int size,space;
cout << "Input size: ";
cin >> size;
int rows = (size * 2)+1;
for (int i = 1, k = 0; i <= rows; ++i, k = 0)
{
for (space = 1; space <= rows - i; ++space)
{
cout << " ";
}
while (k != 2 * i - 1)
{
cout << "* ";
++k;
}
cout << endl;
}
{
for (int i = size; i >= 1; --i)
{
for (int space = 0; space < size - i; ++space)
cout << " ";
for (int j = i; j <= 2 * i - 1; ++j)
cout << "* ";
for (int j = 0; j < i - 1; ++j)
cout << "* ";
cout << endl;
}
}
I try to print a Inverted first, but I fail to print two at the same time.
Related
the problem arises when I use a different number of rows and columns, for example, 2 by 3 otherwise, it is running okay. the sum of column outputs garbage values
I can't seem to understand where the bug is.
#include <iostream>
#include <conio.h>
using namespace std;
int main ()
{
int a[10][10];
int i,row,column, j, s = 0, sum = 0;
cout<<"Enter Number of rows: ";
cin>>row;
cout<<"Enter Number of columns: ";
cin>>column;
cout<< "Enter elements Matrix \n";
for (i = 0; i < row; i++)
for (j = 0; j < column; j++)
cin >> a[i][j];
cout << "Matrix Entered By you is \n";
for (i = 0; i < row; i++)
{
for (j = 0; j <column; j++)
cout << a[i][j] << " ";
cout << endl;
}
for (i = 0; i < row; i++)
{
for (j = 0; j <column; j++)
s = s + a[i][j];
cout << "Sum of Row " << i + 1 << " is: " << s;
s = 0;
cout << endl;
}
cout << endl;
for (i = 0; i < row; i++)
{
for (j = 0; j < column; j++)
s = s + a[j][i];
cout << "Sum of Column " << i + 1 << " is: " << s;
s = 0;
cout << endl;
}
}
You are not iterating correctly to get your columns sum, column and row are switched up. change to:
for (i = 0; i < column; i++) // <-----
{
for (j = 0; j < row; j++) // <-----
s = s + a[j][i];
cout << "Sum of Column " << i + 1 << " is: " << s;
s = 0;
cout << endl;
}
Consider a 3x4 matrix:
1 2 3 4
1 2 3 4
1 2 3 4
Your current loop would access it in the following manner, invoking undefined behavior.
[1] [2] [3] 4
[1] [2] [3] 4
[1] [2] [3] 4
[?] [?] [?]
Im trying to create a program that creates two 2d dynamic arrays and multiply them and give an output and calculate the time taken for the multiplication process based on the input size n. This code works when it comes to outputs lesser than 7 rows and 7 cols but gives an error when the number goes above 8.
using namespace std;
int m1c , m1r , m2c , m2r , i , j , k , l;
int** arr1 = new int*[m1c];
int** arr2 = new int*[m2c];
int** multArr = new int*[m1c];
int main(){
cout << "Enter the Number of rows for matrix 1 :";
cin >> m1c;
cout << "Enter the Number of columns for matrix 1 :";
cin >> m1r;
cout << "Enter the Number of rows for matrix 2 :";
cin >> m2c;
cout << "Enter the Number of columns for matrix 2 :";
cin >> m2r;
for (i = 0; i < m1r; i++) {
arr1[i] = new int[m1c];
multArr[i] = new int[m1c];
}
for (i = 0; i < m2r; i++) {
arr2[i] = new int[m2c];
}
if (m1r != m2c) {
cout << "Number of rows in the first matrix must be equal to the numbr of columns in the second matrix ";
return -1;
}
for (i = 0; i < m1r; i++) {
for (j = 0; j < m2c; j++) {
arr1[i][j] = rand() % 100;
}
}
for (i = 0; i < m2r; i++) {
for (j = 0; j < m2c; j++) {
arr2[i][j] = rand() % 100;
}
}
//Displaying the two arrays
for (i = 0; i < m1r; i++) {
for (j = 0; j < m1c; j++) {
cout << arr1[i][j] << " ";
}
cout << endl;
}
cout << endl;
for (i = 0; i < m2r; i++) {
for (j = 0; j < m2c; j++) {
cout << arr2[i][j] << " ";
}
cout << endl;
}
delete[] arr1;
delete[] arr2;
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Looks like an error initializing arr1. Your using m2c as the column count. You probably meant m1c.
Consider two sets retained in two arrays. Find the union, intersection and difference (relative complement) of the two sets.
I managed to solve the union and the intersection, but the difference is giving me a hard time. Any hints? And if possible, keep it as simple as possible, without functions or more complex aspects, because I'm a beginner and I still have a lot to learn.
Thank you in advance!
#include <iostream>
using namespace std;
int main()
{
int v1[100], v2[100], u[200], intersection[100], d[100];
unsigned int v1_length, v2_length, i, j, OK = 0, union_length;
cout << "Enter the number of elements of the first array:" << " ";
cin >> v1_length;
cout << "Enter the elements of the first array:" << '\n';
for (i = 0; i < v1_length; i++)
cin >> v1[i];
cout << "Enter the number of elements of the second array:" << " ";
cin >> v2_length;
cout << "Enter the elements of the second array:" << '\n';
for (i = 0; i < v2_length; i++)
cin >> v2[i];
//Union
union_length = v1_length;
for (i = 0; i < v1_length; i++)
u[i] = v1[i];
for (i = 0; i < v2_length; i++)
{
int ok = 0;
for (j = 0; !ok && j < v1_length; j++)
if (v1[j] == v2[i])
ok = 1;
if (!ok)
{
u[union_length] = v2[i];
union_length++;
}
}
cout << "The union of the two sets contained in the arrays is: ";
for (i = 0; i < union_length; i++)
cout << u[i] << " ";
cout << '\n';
//Intersection
unsigned int k = 0;
cout << "The intersection of the two sets contained in the arrays is: ";
for (i = 0; i < v1_length; i++)
for (j = 0; j < v2_length; j++)
if (v1[i] == v2[j])
{
intersection[k] = v1[i];
k++;
}
for (i = 0; i < k; i++)
cout << intersection[i] << " ";
cout << '\n';
//Difference
unsigned int l = 0, OK2 = 0;
cout << "The difference of the two sets contained in the arrays is: ";
for (i = 0; i < v1_length; i++)
{
for (j = 0; j < v2_length; j++)
{
if (v1[i] == v2[j])
OK2 = 1;
if (!OK2)
{
d[l] = v1[i];
l++;
}
}
}
for (i = 0; i < l; i++)
cout << d[i] << " ";
cout << '\n';
return 0;
}
It seems that the intersection is the best place to start. You want the items that only in appear in one of the two arrays, right?
So, for the inner loop, you need to compare all the elements. Then, if no match was found, you have the a unique element.
You need to add the curly braces {} to the for loop. I know that curly braces are distracting at times, but over time, you will probably find it safer to almost always include them to avoid confusion.
for (i = 0; i < v1_length; i++)
for (j = 0; j < v2_length; j++) {
if (v1[i] == v2[j]){
break; // this item is not unique
} else if(j == v2_length - 1){
d[l] = v1[i]; // This is the unique one, add it to the answer array
l++;
}
}
for (i = 0; i < l; i++)
cout << intersection[l] << " ";
cout << '\n';
You're on the right track!
You're doing a few things wrong. Here are some fixes you can try:
Only set OK2 to 0 once per inner-loop
Reset OK2 to 0 at the end of the inner-loop
Only do the insertion into d after the inner-loop has completed
As an optimization, consider breaking after you set OK2 to 1, as you know at that point it can never be set to 0 for the current value pointed to by the outer-loop.
So, I am trying to implement this algorithm from our textbook.
I wrote this :
// Knapsack_memoryfunc.cpp : Defines the entry point for the console application.
//Solving Knapsack problem using dynamic programmig and Memory function
#include "stdafx.h"
#include "iostream"
#include "iomanip"
using namespace std;
int table[20][20] = { 0 };
int value, n, wt[20], val[20], max_wt;
// ---CONCERNED FUNCTION-----
int MNSack(int i, int j)
{
value = 0;
if (table[i][j] < 0)
if (j < wt[i])
value = MNSack(i - 1, j);
else
value = fmax(MNSack(i - 1, j), val[i] + MNSack(i - 1, j - wt[i]));
table[i][j] = value;
return table[i][j];
}
// --------------------------
void items_picked(int n, int max_wt)
{
cout << "\n Items picked : " << endl;
while (n > 0)
{
if (table[n][max_wt] == table[n - 1][max_wt]) // if value doesnot change in table column-wise, item isn't selected
n--; // n-- goes to next item
else // if it changes, it is selected
{
cout << " Item " << n << endl;
max_wt -= wt[n]; // removing weight from total available (max_wt)
n--; // next item
}
}
}
int main()
{
cout << " Enter the number of items : ";
cin >> n;
cout << " Enter the Maximum weight : ";
cin >> max_wt;
cout << endl;
for (int i = 1; i <= n; i++)
{
cout << " Enter weight and value of item " << i << " : ";
cin >> wt[i] >> val[i];
}
for (int i = 0; i <= n; i++)
for (int j = 0; j <= max_wt; j++)
table[i][j] = 0;
for (int i = 1; i <= n; i++)
for (int j = 1; j <= max_wt; j++)
table[i][j] = -1;
cout << " Optimum value : " << MNSack(n, max_wt);
cout << " \n Table : \n";
for (int i = 0; i <= n; i++)
{
for (int j = 0; j <= max_wt; j++)
if (table[i][j] == -1)
cout << setw(5) << "-";
else
cout << setw(5) << table[i][j];
cout << endl;
}
items_picked(n, max_wt);
return 0;
}
Here is the question and output :
It seems like its correct on some places like optimum value, yet isn't fully acceptable.
I've tried to debug it, but its quite hard with recursive functions. Can someone please help?
int MNSack(int i, int j)
{
value = 0;
if (table[i][j] < 0)
{
if (j < wt[i])
value = MNSack(i - 1, j);
else
value = max(MNSack(i - 1, j), val[i] + MNSack(i - 1, j - wt[i]));
table[i][j] = value;
}
return table[i][j];
}
The problem comes in here. When your table item is greater or equal to 0, you will skip the recursion but still set the table item to 0, which won't be right if your table item is greater than 0.
You only need to update the table item when it needs to be change, so put it in the braces will correct this.
The bottom up solution.
#include <iostream>
#include <algorithm>
#include <iomanip>
using namespace std;
int main()
{
int table[20][20] = { 0 };
int value, n, wt[20], val[20], max_wt;
cout << " Enter the number of items : ";
cin >> n;
cout << " Enter the Maximum weight : ";
cin >> max_wt;
cout << endl;
for (int i = 1; i <= n; i++)
{
cout << " Enter weight and value of item " << i << " : ";
cin >> wt[i] >> val[i];
}
// Initialization
for (int i = 0; i <= n; i++)
for (int j = 0; j <= max_wt; j++)
table[i][j] = 0;
// In practice, this can be skipped in a bottom up solution
for (int i = 1; i <= n; i++)
for (int j = 1; j <= max_wt; j++)
table[i][j] = -1;
for (int i = 1; i <= n; i++)
{
for (int j = 1; j <= max_wt; j++)
{
if (j < wt[i])
table[i][j] = table[i - 1][j];
else
table[i][j] = max(table[i - 1][j], val[i] + table[i - 1][j - wt[i]]);
}
}
cout << " Optimum value : " << table[n][max_wt] << endl;
cout << " \n Table : \n";
for (int i = 0; i <= n; i++)
{
for (int j = 0; j <= max_wt; j++)
if (table[i][j] == -1)
cout << setw(5) << "-";
else
cout << setw(5) << table[i][j];
cout << endl;
}
return 0;
}
You can see that this changes the recursion to a loop, and therefore avoids the global variables. It also makes the code simpler, so that you can avoid checking if the table item is valid (equal to -1 in your example).
The drawback of this solution is, it always traverses all the possible nodes. But it gains better coefficient per item because the recursion and double checking the table item costs more. Both top-down and bottom-up have the same order of complexity O(n^2), and it's hard to tell which one is faster.
Im supposed to display grades in a graph that shows how many grades are in each interval 0-10, 10-20, 20-30 etc. By putting a * for each grade in the interval. My only problem is that when the array grade[] has 1, 2, 3 or 5 slots it puts an extra * in the 0-10 interval. It works with every other ammount of slots.
void sort_grades(int grades[],int students)
cout << endl << endl;
cout << " THE GRADES GRAPH"<< endl;
cout << "=============================="<<endl;
const int max_grade = 100;
const int interval=10;
for (int j = 0; j < max_grade; j+=10)
{
cout << j << " - " << (j+interval) << " : ";
for (int k = 0; k <= students; k++)
{
if (j==90 && grades[k] ==(j+interval) )
{
cout<< "*";
}
else if (grades[k] < (j+interval) && grades[k] >= j)
{
cout<< "*";
}
}
cout << endl;
}
I assume that students is the size of the array grades[].
In this case, you access too many elements in the following loop:
for (int k = 0; k <= students; k++)
Instead the line should read:
for (int k = 0; k < students; k++)
This problem does not only occur for the cases where grade[] has a size of 1, 2, 3 or 5. You only see the problem for that sizes, because the output depends on the content of the array.