Description
This code is intended to find a spanner index (i) when dealing with
Splines/NURBS basis functions based on a knot vector (U), a choosen knot (u), the degree of the desired curve (p) and the number of basis funcions (n). The algorithm was taken from the NURBS Book by Piegl and Tiller. The error, I guess, is in the way I declared variable U. Thaks in advanced!
code
# include <iostream>
using namespace std;
int n=3;
int p=2;
double u=5/2;
int U[11]={0,0,0,1,2,3,4,4,5,5,5};
int FindSpan(n,p,u,U) /* an error in this line */
{
if (u==U[n+1]) return (n);
low=p; high=n+1;
mid=(low+high)/2
while(u<U[mid] || u>=U[mid+1])
{
if (u<U[mid]) high=mid;
else low=mid;
mid=(low+high)/2
}
return (mid);
}
You have forgotten some semicolons and types!
here is the correct code:
#include <iostream>
using namespace std;
int n=3;
int p=2;
double u=5/2;
int U[11]={0,0,0,1,2,3,4,4,5,5,5};
int FindSpan(int n, int p, int u, int U[])
{
if (u==U[n+1]) return (n);
int low=p, high=n+1;
int mid=(low+high)/2;
while(u<U[mid] || u>=U[mid+1])
{
if (u<U[mid]) high=mid;
else low=mid;
mid=(low+high)/2;
}
return (mid);
}
int main() {
cout << FindSpan(n, p, u, U);
return 0;
}
Related
I have used Dynamic Programming to find longest common sub-sequence b/w two strings. What is wrong in the code. Why it always gives answer as 0?
#include<bits/stdc++.h>
using namespace std;
int dp[20][20];
void initialize()
{
for(int i=0;i<20;i++)
for(int j=0;j<20;j++)
dp[i][j]=-1;
}
int lcs(string a,string b,int m,int n)
{
if(m==0||n==0)
return 0;
if(dp[m][n]!=-1)
return dp[m][n];
if(a[m-1]==b[n-1])
return dp[m-1][n-1] = 1+lcs(a,b,m-1,n-1);
if(a[m-1]!=b[n-1])
return dp[n-1][m-1]=max(dp[n][m-1]=lcs(a,b,n,m-1),dp[n-1][m]=lcs(a,b,n-1,m));
}
int main()
{
string a="AGGTAB",b="GXTXAYB";
cout<<lcs(a,b,a.length(),b.length());
}
You've forgotten to call initialize()
18th line, it should be dp[m][n], not dp[m-1][n-1]
Commented 19th line code, as it is no need & for make the code compatible for all compilers
i.e., some compiler may give warning: control reaches end of non-void function [-Wreturn-type]
Made some code change in 20th line, as it seems you confused with variables m & n.
Code:
#include<bits/stdc++.h>
using namespace std;
int dp[20][20];
void initialize()
{
for(int i=0;i<20;i++)
for(int j=0;j<20;j++)
dp[i][j]=-1;
}
int lcs(string a,string b,int m,int n)
{
if(m==0||n==0)
return 0;
if(dp[m][n]!=-1)
return dp[m][n];
if(a[m-1]==b[n-1])
return dp[m][n] = 1+lcs(a,b,m-1,n-1);
//if(a[m-1]!=b[n-1])
return dp[m][n]=max(lcs(a,b,m-1,n),lcs(a,b,m,n-1));
}
int main()
{
string a="AGGTAB",b="GXTXAYB";
initialize();
cout<<lcs(a,b,a.length(),b.length());
}
Output:
4
I'm very new to C++, so I've probably made some really stupid mistakes. But I've looked online to solutions for this error, and I tried all I can think of.
I'm trying to have my whole program in one function, because it's going to be merged with other programs. The id error is the only error I have so far.
#include<stdio.h>
#include<stdlib.h>
#include<ctype.h>
#include<string.h>
using namespace std;
int ninebooking(int Endor=0, int Naboo=0, int tatooine=0);
int sevenbooking(int Endor=0, int Naboo=0, int tatooine=0);
void BookingSystem(int time, int k);
int time;
int k = 0;
int main()
{
BookingSystem(time, k);
{
while (k==0)
{
printf("\n\nMeals are served at 9pm and 7pm, please enter what time you would like to book for");
scanf("You have selected to book your meal for %d", &time);
if (time!=7||time!=9)
{
printf("Sorry, that was an incorrect time");
time = 0;
}
}
return 0;
}
system ("pause");
return 0;
}
Any help is much appreciated, I've spent a long time trying to fix this on my own with no luck.
Thank you!
You make many mistakes in your program:
1) You mix C & C++ syntax.
using namespace std, is C++
2) You include useless header files
3) You declare variables that I don't understand what for
Why do you need this?
int ninebooking(int Endor=0, int Naboo=0, int tatooine=0);
int sevenbooking(int Endor=0, int Naboo=0, int tatooine=0);
You don't use the variables above anywhere !!!!
4) You try to write a function inside main (this is not Pascal).
So, if I understand what you want, look at this:
#include <stdio.h>
void BookingSystem() // this is the function who does all job
{
int time = 0;
while ((time != 7) && (time != 9))
{
printf("\n\nMeals are served at 9pm and 7pm, please enter what time you would like to book for");
printf("\nYou have selected to book your meal for ");
scanf("%d", &time); // read the time
scanf("%*[^\n]"); // consume all caracters until the newline
scanf("%*c"); // consume the newline
if (time == 7)
{
printf("You have selected to book your slot at 7PM\n");
}
else if (time == 9)
{
printf("You have selected to book your slot at 9PM\n");
}
else
{
printf("You have selected an incorrect time, please try again\n");
}
} // end while
} // end function
int main(int argc, char *argv[])
{
BookingSystem(); // this is the calling to your function
return 0;
}
If I understand what you want, this works fine.
you can not to Define Function in to the main ..
you must to do like this...
#include<stdio.h>
#include<stdlib.h>
#include<ctype.h>
#include<string.h>
using namespace std;
int ninebooking(int , int , int ); //just say data type int or ....
int sevenbooking(int , int , int );
void BookingSystem(int , int);
int main() //and in to main just call he...
{
int time;
int k = 0;
BookingSystem(time, k);//call ....and send parameter time and k
system ("PAUSE");
return 0;
}
void BookingSystem(int time,int k)
{
while (k==0)
{
printf("\n\nMeals are served at 9pm and 7pm, please enter what time you would like to book for");
scanf("You have selected to book your meal for %d", &time);
if (time!=7||time!=9)
{
printf("Sorry, that was an incorrect time");
time = 0;
}
}
// return 0;//if this function is void he can not to return any thing!!!!
}
int ninebooking(int Endor=0, int Naboo=0, int tatooine=0)
{
//......
}
int sevenbooking(int Endor=0, int Naboo=0, int tatooine=0)
{
//........
}
This cpp code is not terminating. I have tried the code by various inputs but this is not terminating.I think there is a bug in the 52th line, when I comment the 52 line than the code is working fine.
#include<cstdio>
#include<iostream>
#include<vector>
#include<algorithm>
// binary search for larger elements
using namespace std;
vector <int > q;
// bsearch value uses hte
#define bvector q // just define these values to use them in your functin
#define VALUE(x) bvector[x]
int b_search(int value){
int low=0,high=bvector.size(),mid;
mid=(low+high)/2;
cout << "In the bsearch";
while(low<high)
{
if(VALUE(mid)==value)
return mid;
else if(VALUE(mid)>value)//
high=mid;
else if(VALUE(mid)<value)
low=mid+1;
}
if(VALUE(low)>value)
return low;
return -1;
}
int main(){
int i;
for(scanf("%d",&i);i;scanf("%d",&i))
q.push_back(i); // this is for taking input in the vectot
sort(q.begin(),q.end());
for(i=0;i<q.size();i++)
printf("%d ",q[i]);// for printing the sorted
int j;
printf("Enter the elements you want to search");
int x;
scanf("%d",&x);
// BUG is present in this lines
cout <<"This is the end of scanf";// if this line is commented then the 54th line is not reached
j=b_search(x);
printf("%d ",j);
return 0;
}
The statement : mid=(low+high)/2; is a bit misplaced. It should be inside the while loop.
This is probably what is causing an infinite loop.
While I am trying to compile the code with few modification in binary search recursive function. The program is acting weird. Some time it gives the correct value and some time it goes to infinite loop. Please explain what went wrong with the code. I am using DEV C++ as an IDE.
CODE:
#include<iostream>
#include<sstream>
using namespace std;
//function to compare the two integers
int compare(int low, int high)
{
if (low==high)
return 0;
if (low<high)
return 1;
else
return -1;
}
//Function for binary search using recursion
int *BinarySearch(int *Arr,int Val,int start,int end)
{
int localstart=start;
int localend=end;
int mid=(start+end)/3;
cout<<"MID:"<<mid;
int comp= compare(Val,Arr[mid]);
if(comp==0)
return &(Arr[mid]);
else if (comp>0)
return BinarySearch(Arr,Val,localstart,mid-1);
else
return BinarySearch(Arr,Val,mid+1,localend);
return NULL;
}
main()
{
int *arr;
arr= new int [256];
string str;
getline(cin,str);
stringstream ss;
ss<<str;
int index=0;
while(ss>>arr[index])
{index++;}
//cout<<arr[index-1];
cout<<"Enter Value:";
int value;
cin>>value;
int *final;
final=BinarySearch(arr,value,0,index-1);
if(final!=NULL)
cout<<"Final:"<<*final;
else
cout<<"Not Found";
getchar();
getchar();
return 0;
}
Two ideas:
What should BinarySearch do if Val is not in the array? Trace out what your code does in this case.
(start+end)/3 probably isn't the middle of the current range.
My aim is to construct a binomial heap. Here is my code which i have written right now:
#include<iostream>
using namespace std;
void maxheapify(int a[],int length,int i)
{
int left=2*i;
int right=2*i+1;
int largest=i;
if(left<length && a[left]>a[largest])
{
largest=left;
}
if ( right<length && a[right]>a[largest])
{
largest=right;
}
if(largest!=i)
{
int temp=a[i];
a[i]=a[largest];
a[largest]=temp;
maxheapify(a,length,largest);
}
}
void buildmax(int a[],int length)
{
for(int i=(length-1)/2;i>=0;i--)
{
maxheapify(a,length,i);
}
}
/*void heapsort(int a[],int length)
{
buildmax(a,length);
for(int i=length-1;i>0;i--)
{
int temp=a[i];
a[i]=a[0];
a[0]=temp;
maxheapify(a,i,0);
}
}
*/
void combine_heap(int a[],int n,int b[],int m,int c[])
{
}
int main()
{
int a[100];
int n=sizeof(a)/sizeof(a[0]);
int b[100];
int m=sizeof(b)/sizeof(b[0]);
int c[200];
int length=sizeof(a)/sizeof(a[0]);
for(int i=0;i<length;i++){
a[i]=34+rand()%(length-33);
b[i]=rand()%(i+1);
}
/*heapsort(a,length);*/
/*for(int i=0;i<length;i++)
cout<<a[i]<<" ";*/
return 0;
}
i think trivial solution would be to combine two array into third one and then call buildmax procedure,but i think it is not efficient,i have tried to implement this pseudo code from wikipedia
function merge(p, q)
while not( p.end() and q.end() )
tree = mergeTree(p.currentTree(), q.currentTree())
if not heap.currentTree().empty()
tree = mergeTree(tree, heap.currentTree())
heap.addTree(tree)
else
heap.addTree(tree)
heap.next() p.next() q.next()
but i dont know how to implement it,because in generally how to access subtrees?another variant is construct priority queue and by using insert function insert first from one array and then from another array,but is this optimal?please help me to write code to combine these two max heap into one efficiently
This is a good example of Binomial Heap but it is in c. You will get the basic logic to implement binomial heap. See Example here
Or get video tutorial to here to understand algorithm.