this is my code, PLease help me ! im using xcode.. i want to generate a sequence for a polynomial and the terms are xor'ed and made a feedback to the first input bit since it is 8 bit it is done 2^8-1 times.Alternate code will also be helpful Thanks in advance
#include "32bit.h"
#include<iostream>
using namespace std;
int main()
{
bool input[8];
int n;
bool out=0;
cout<<"Enter the no of terms ";
cin>>n;
int temp1[n];
int gen=0;
bool store[255];
cout<<"Input power of x in increasing order, Omit x^0";
for(int i=0;i<n;i++)
cin>>temp1[i];
cout<<"Enter key to generate ";
cin>>gen;
for(int m=0;m<255;m++)
{
store[m]=input[gen];
bool temp2[n];
int var=0;
for(int j=0;j<n;j++)
{
var=temp1[j];
temp2[j]=input[var];
}
int c=0;
for(int k=0;k<n;k++)
{
if(temp2[k]%2==1)
c++;
}
if(c%2==1)
out=1;
else
out=0;
for(int l=0;l<8;l++)
input[l+1]=input[l];
input[0]=out;
}
for(int p=0;p<255;p++)
cout<<store[p];
}
There is an out of bounds array access here:
for(int l=0;l<8;l++)
input[l+1]=input[l];
since input is only of size 8 and you are trying to write to input[8] (i.e. the non-existent 9th element) on the last iteration of this loop. I'm guessing it should probably be:
for(int l=0;l<7;l++)
input[l+1]=input[l];
Related
I Am Trying To Find Partition Of Array ,On Condition By Checking Variable x ,when less then x they will be on one side or else on another. but my code need some correction.
HERE am not able to find the error , i will be thankful to you if you help me.
Code is:-
#include<iostream>
using namespace std;
int partition(int arr[],int n,int x){
for(int i=0;i<n;){
if(arr[i]<x){
i++;
}
else if(arr[i]==x){
int temp=arr[i];
arr[i]=arr[n];
arr[n]=temp;
i--;
}
else if(arr[i]>x){
int temp=arr[i];
for(int j=i;j<n;j++){
arr[j]=arr[j+1];
}
arr[n]=temp;
i--;
}
}
return 0;
}
int main(){
int n;
cin>>n;
int arr[n];
for(int i=0;i<n;i++){
cin>>arr[i];
}
int x;
cin>>x;
partition(arr,n,x);
for(int i=0;i<n;i++){
cout<<arr[i]<<"\t";
}
return 0;
}
Input >> array={2,10,15,1,3,15} ,x=10
Expected << {2,1,3,10,15,15}
Output I get << nothing .
The code isn't giving any output because, first, the "cin" and "cout" are in upper case which is syntactically incorrect, secondly, the variable j is in different case in loop statement and body inside the second else-if clause in the partition function, same goes for the "I" in the first for loop in the main() function. Sort this out and you should be good to go.
First in C++ the size of an array must be a compile-time constant. So for example, consider the following examples:
int n = 10;
int arr[n]; //INCORRECT
The correct way to write the above would be:
const int n = 10;
int arr[n]; //CORRECT
Similarly, in your code,
int n;
cin>>n;
int arr[n]; //INCORRECT because n is not a constant expression
Second, in your code, when you wrote:
arr[n] = temp; Undefined behavior
you're going out of bounds and so you have undefined behavior.
Solution
You can use std::stable_partition and std::vector to solve your problem as shown below:
#include <iostream>
#include <vector>
#include <algorithm>
int main()
{
int n;
std::cout <<"Enter n:"<<std::endl;
std::cin >> n;
std::vector<int> arr(n); //create a vector of size n instead of an array
std::cout<<"Enter elements: "<<std::endl;
//iterate and take input from user
for(int &elem: arr){
std::cin >> elem ;
}
int x;
std::cout << "Enter x: "<<std::endl;
std::cin>>x;
//use std::partition
std::stable_partition(arr.begin(), arr.end(), [x](int i){return (i < x);});
std::cout<<"This is the partitioned vector: "<<std::endl;
for(int i=0;i<n;i++)
{
std::cout<<arr[i]<<"\t";
}
return 0;
}
Output
The output of the above program is as follows:
Enter n:
6
Enter elements:
2
10
15
1
3
15
Enter x:
10
This is the partitioned vector:
2 1 3 10 15 15
which can be seen here.
I wrote a program of Insertion sort in c++ but output screen does not showing any Statement.I am facing this problem in few another program.
This is the code:
#include<iostream>
using namespace std;
int main()
{
int n;
int arr[n];
cout<<"Enter the number of the element of the Array:";
cin>>n;
cout<<"Enter the element of the Array:";
for(int i=0;i<n;i++){
cin>>arr[i];
}
for(int i=0;i<n;i++){
int current=arr[i];
int j=i-1;
while(arr[j]>current && j>=0){
arr[j+1]=arr[j];
j--;
}
arr[j+1]=current;
}
for(int i=0;i<n;i++){
cout<<arr[i]<<" ";
}cout<<endl;
return 0;
}
You are using the value of n before it has a value. Change your code to this
int n; // n does not have a value
cout<<"Enter the number of the element of the Array:";
cin>>n; // n gets value here
int arr[n]; // n is used here
You cannot use any variable before it has a value. That's a fundamental rule of C++.
You cannot creat variable C-style arrays during run time.
You should either create them with the new operator or switch to STL containers like std::vector.
My code is showing TLE when there when number of entries in array(n) is 1 *10^5. What should i do? I saw the submission status and in all cases it ran fine except in the last case when n is 100 000, it shows time limit error.
Problem:: https://codeforces.com/contest/474/problem/B
My solution: https://pastebin.com/5RLBirpF
Code:
#include <iostream>
#include<bits/stdc++.h>
using namespace std;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
int t;
cin>>t;
int arr[t];
int arrfreq[t];
int sum=1;
for(int i=0;i<t;i++ )
{
cin>>arr[t];
sum+=arr[t];
arrfreq[i]=sum;
}
int m;
cin>>m;
int qsn[m];
int k;
for(int i =0;i<m;i++)
{
cin>>qsn[i];
}
for(int j =0;j<t;j++)
{
if(k<arrfreq[j])
{
cout<<j+1<<"\n";
break;
}
if(k==arrfreq[j])
{
cout<<j+2<<"\n";
break;
}
}
}
You are using one loop for calculating the number of pile. What you can do instead is find the answer in the same loop in which you are taking the input for qsn. Just take the input of qsn and find the pile number in that loop itself. That will reduce your code's time complexity and remove the TLE error.
I saw other solutions on the internet and found out that std::lower_bound function is what has to be used to avoid T.L.E.
But one thing, as mentioned on internet, this function returns a pointer to the lower bound, then , why are we subtracting c from it and then +1 also(in the 2nd last cout line)??(refer to the code.)
#include <bits/stdc++.h>
using namespace std;
int main()
{
int n,i,m,j,cnt=0,ans,x,sum=0;
cin>>n;
int a[n],c[n];
for(i=0; i<n; i++){
cin>>a[i];
sum+=a[i];
c[i]=sum;
}
cin>>m;
int b[m];
for(i=0; i<m; i++) cin>>b[i];
for(j=0; j<m; j++)
{
cout<<lower_bound(c,c+n,b[j])-c+1<<endl;
}
return 0;
}
I am trying to use bubble sort method for array with dynamically determined size. Here's the code:
#include <iostream>
using namespace std;
int main()
{
int n;
cout<<"Enter n";
cin>>n;
int arr[n],swap;
cout<<"Enter number"<<endl;
cin>>arr[n];
for(int i=0;i<n-1;i++)
for(int j=0;i<n-i-1;j++)
if(arr[j]>arr[j+1])
{
swap=arr[j];
arr[j]=arr[j+1];
arr[j+1]=swap;
}
for(int k=0;k<n;k++)
cout<<"arr["<<k<<"]="<<arr[k]<<endl;
return 0;
}
When I define the elements of the array in this way the program works:
const n=5;
int arr[n]={1,2,3,4,5)
But I need to enter the size of the array (n) and its elements from the keyboard. But when I run my code the program crashes after I enter the first number. Is there a way to fix it?
#include <iostream>
#include <vector>
using namespace std;
int main()
{
int n, swap, temp;
vector<int> arr;
cout<<"Enter n";
cin>>n;
// Loop and accept the n values.
// You may need to take care of the new line.
for(int i = 0; i < n; ++i)
{
cout << "Enter a number : ";
cin >> temp;
arr.push_back(temp);
}
for(int i=0;i<n-1;i++)
for(int j=0;j<n-i-1;j++)
if(arr[j]>arr[j+1])
{
swap=arr[j];
arr[j]=arr[j+1];
arr[j+1]=swap;
}
for(int k=0;k<n;k++)
cout<<"arr["<<k<<"]="<<arr[k]<<endl;
return 0;
}
Notice how a loop is used to extract n values from user. Also using a std::vector relieves you from writing code for a runtime sized array with new and delete.
Also, you inner loop was checking i<n-i-1 and incrementing j which should be j<n-i-1 instead, otherwise j will increment indefinitely till INT_MAX.
The key word is dynamic allocation. In C, the function is malloc. In Cpp, it can be new and delete. Although a vector can work well, it is just a kind of method by STL. Notice that my code may have safe problem.
#include <iostream>
using namespace std;
int main()
{
int n,temp;
cout<<"Enter n:";
cin>>n;
//dynamic allocation
int *arr=new int[n];
cout<<"Enter number."<<endl;
for(int i=0;i<n;i++){
cin>>arr[i];
}
//bubble sort
for(int i=0;i<n;i++){
for(int j=i;j<n;j++){
if(arr[i]>arr[j]){
temp=arr[i];
arr[i]=arr[j];
arr[j]=temp;
}
}
}
//output the array
for(int i=0;i<n;i++){
cout<<"arr["<<i<<"]="<<arr[i]<<endl;
}
delete [] arr;
return 0;
}
You can't take an integer array like that, you need to run a loop. You can take a string like that. There are lot of errors in the bubble sort logic as well, try the below code snippet. It should work fine. You need to dynamically allocate the array for arr
int n,r,swap,i,*arr;
cout<<"Enter n\n";
cin>>n;
arr = (int *)malloc((n)*sizeof(int));
cout<<"Enter numbers\n"<<n<<endl;
for(i=0;i<n;i++)
{
cin>>arr[i];
}
for(i=0;i<n;i++)
{
for(int j=0;j<n-1;j++)//You're checking for i. you need to check for j
{
if(arr[j+1]<arr[j])
{
swap=arr[j];
arr[j]=arr[j+1];
arr[j+1]=swap;
}
}
}
//now print your arr
Includes : #include<stdlib.h>
As mentioned in my comment, you CANNOT dynamically declare the size of arrays in C++ (use std::vector if you are willing to achieve that).
You can then do this:
....
cin >> n;
vector<int> arr(n); // reserves space for `n` integers in the memory
....
Hi I started doing code chef beginner problems and got stuck at this one.I tried reducing the stack memory by declaring the arrays globally but that doesn't work too.Here is my code
#include<iostream>
using namespace std;
#define max 101
int main()
{
int t,n;
cin>>t;
while(t--)
{
int a[max];
int c[max]={0};
cin>>n;
for(int i=0;i<n;i++)
{
cin>>a[i];
}
for(int j=0;j<n;j++)
{
c[a[j]]++;
}
int temp=0;
int x=0;
for(int k=0;k<n;k++)
{
if(c[k]>temp)
{
temp=c[k];
x=k;
}
}
cout<<x<<" "<<temp<<endl;
}
}
You may need a data structure that does not limit the input value to be bounded, or just change your algorithm.
Either use std::map<int, int> in place of c to count occurence of each number, or just sort a to aggregate same values and count.