here is my code, I can not figure out why it won't work as a function when the exact code in main() produces the correct answer. The assignment is to convert binary number to decimal.
#include <iostream>
#include <cstdlib>
#include "std_lib_facilities.h"
using namespace std;
int binaryCon(int biNum);
int main()
{
int num, bin, Bnum;
cout << "Enter the binary number(1s and 0s) : ";
cin >> num;
bin = num;
Bnum = binaryCon(num);
cout << "The decimal equivalent of " << bin << " : " << Bnum << endl;
}
int binaryCon(int biNum)
{
long dec = 0, rem = 0, base = 1;
enter code here`while (biNum > 0)
rem = biNum % 10;
dec = dec + rem * base;
base = base * 2;
biNum = biNum / 10;
return biNum;
}
corrected code:
#include <iostream>
#include <cstdlib>
using namespace std;
int binaryCon(int biNum);
int main()
{
int num, bin, Bnum;
cout << "Enter the binary number(1s and 0s) : ";
cin >> num;
bin = num;
Bnum = binaryCon(num);
cout << "The decimal equivalent of " << bin << " : " << Bnum << endl;
getchar();
return 0;
}
int binaryCon(int biNum)
{
long dec = 0, rem = 0, base = 1;
while (biNum > 0){
rem = biNum % 10;
dec = dec + rem * base;
base = base * 2;
biNum = biNum / 10;
}
return dec;
}
As you are not using { and } in your while loop may be its going in infinite loop. As its working for this line only
while (biNum > 0)
rem = biNum % 10; // running this line infinite as `biNum > 0`
Use
while (biNum > 0){
rem = biNum % 10;
dec = dec + rem * base;
base = base * 2;
biNum = biNum / 10;
}
maybe this?
while (biNum > 0)
{
rem = biNum % 10;
dec = dec + rem * base;
base = base * 2;
biNum = biNum / 10;
}
int main() or int main(int argc, char** argv) must return a value. If you return 0 then it means that there is no problem with code. Another numbers 1,2 etc means there is an error.(Returned numbers are error numbers)
Related
I am still learning about threads and I was trying to solve this problem in my code, when I am putting the pthread_join(thread[i],NULL) outside the loop that is creating the threads it always gives me wrong output and Thread with ID = 0 will not work(call the median func) and the last thread will work two times, for better understanding see the output below:
ThreadID= 0, startRow= 0, endRow= 0 // first thread doesn't call the median func
ThreadID= 1, startRow= 1, endRow= 1
ThreadID 1 numOfBright 0 numOfDark 1 numOfNormal 4
ThreadID= 2, startRow= 2, endRow= 2
ThreadID 2 numOfBright 0 numOfDark 1 numOfNormal 4
ThreadID= 3, startRow= 3, endRow= 3
ThreadID 3 numOfBright 0 numOfDark 0 numOfNormal 5
ThreadID= 4, startRow= 4, endRow= 4
ThreadID 4 numOfBright 0 numOfDark 5 numOfNormal 0
ThreadID 4 numOfBright 0 numOfDark 5 numOfNormal 0 // last thread is calling the median func two times.
This is the part of the code that prints the start and end row of each thread.
pthread_t* threads = new pthread_t[num_threads];
struct Th_Range* RANGE = (struct Th_Range*)malloc(sizeof(struct Th_Range*));
int thread_status;
RANGE->SizeOfImage = r; // 2d array with size (n*n) so rows(r) = columns(c)
if (n == num_threads) { //rows = num of threads then every thread will work in a single row
for (int i = 0; i < num_threads; i++) {
RANGE->ThreadId = i;
RANGE->StartRow = RANGE->EndRow = i;
cout << "ThreadID= " << i << ", startRow= " << RANGE->StartRow << ", endRow= " << RANGE->EndRow << endl;
thread_status = pthread_create(&threads[i], NULL, Median, RANGE);
if (thread_status)
exit(-1);
} //for loop ends here
for (int i = 0; i < num_threads; i++)
pthread_join(threads[i],NULL);
} //end of if statement
Here is the part of the code if needed with the median function and the above if statement.
#include <iostream>
#include <bits/stdc++.h>
#include <pthread.h>
pthread_mutex_t Lock;
pthread_mutex_t Pixels;
pthread_mutex_t Pixels2;
using namespace std;
int numOfBright, numOfDark, numOfNormal;
int** Oimage, ** Fimage; //original and filtered image
struct Th_Range {
int SizeOfImage;
int StartRow;
int EndRow;
int ThreadId;
};
void* Median(void* par)
{
struct Th_Range* Num = (struct Th_Range*)par;
int StartRow = Num->StartRow;
int EndRow = Num->EndRow;
int Size = Num->SizeOfImage;
int Neighbour[9] = { 0 };
int dark = 0, bright = 0, normal = 0;
if (EndRow == StartRow)
EndRow += 2;
else
EndRow++;
for (int i = StartRow +1; i < EndRow ; i++)
{
for (int j = 1; j < Size - 1; j++)
{
Neighbour[0] = Oimage[i - 1][j - 1];
Neighbour[1] = Oimage[i - 1][j];
Neighbour[2] = Oimage[i - 1][j + 1];
Neighbour[3] = Oimage[i][j - 1];
Neighbour[4] = Oimage[i][j];
Neighbour[5] = Oimage[i][j + 1];
Neighbour[6] = Oimage[i + 1][j - 1];
Neighbour[7] = Oimage[i + 1][j];
Neighbour[8] = Oimage[i + 1][j + 1];
pthread_mutex_lock(&Pixels); //it can be moved only to lock the Fimage and the numOfBright or any other global variables
sort(Neighbour, Neighbour + 9);
Fimage[i][j] = Neighbour[4];
if (Neighbour[4] > 200) {
bright++;
numOfBright++;
}
else if (Neighbour[4] < 50) {
dark++;
numOfDark++;
}
else {
normal++;
numOfNormal++;
}
pthread_mutex_unlock(&Pixels);
}
}
pthread_mutex_lock(&Pixels2); //when I try to remove this lock the output gets interrupted
cout << "ThreadID " << Num->ThreadId << " numOfBright " << bright << " numOfDark " << dark << " numOfNormal " << normal<<endl;
pthread_mutex_unlock(&Pixels2);
pthread_exit(NULL);
}
int main(int argc, char* argv[])
{
int num_threads, n, r, c; // n is the size of the matrix r and c are rows and columns
numOfNormal = numOfDark = numOfBright = 0;
if (argc >= 2)
num_threads = atoi(argv[1]);
else
exit(-1);
ifstream cin("input.txt");
cin >> n;
r = c = n + 2;
Oimage = new int* [r]();
Fimage = new int* [r]();
for (int i = 0; i < c; i++)
{
Oimage[i] = new int[c]();
Fimage[i] = new int[c]();
}
for (int i = 1; i < r - 1; i++)
for (int j = 1; j < c - 1; j++)
cin >> Oimage[i][j];
pthread_t* threads = new pthread_t[num_threads];
struct Th_Range* RANGE = (struct Th_Range*)malloc(sizeof(struct Th_Range*));
RANGE->SizeOfImage = r;
if (n == num_threads) { //rows = num of threads then every thread will work in a single row
//n+2
int thread_status;
for (int i = 0; i < num_threads; i++) {
RANGE->ThreadId = i;
RANGE->StartRow = RANGE->EndRow = i;
// pthread_mutex_lock(&Lock);
cout << "ThreadID= " << i << ", startRow= " << RANGE->StartRow << ", endRow= " << RANGE->EndRow << endl;
thread_status = pthread_create(&threads[i], NULL, Median, RANGE);
if (thread_status)
exit(-1);
}
}
I tried to move pthread_join inside the loop of pthread_create it gives a correct output but of course it is a wrong solution. I have no idea what to do next. Thanks in advance
Maybe you should use #include
or (using namespace sff) it must work
I have looked extensively for the problem in this code, but I can't seem to figure out what tragic error I made and why it is triggering a breakpoint.
(After 3 or 4 inputs, it triggers and I don't know why it doesn't trigger at the start or what is causing it)
#include <conio.h> // For function getch()
#include <cstdlib> // For several general-purpose functions
#include <fstream> // For file handling
#include <iomanip> // For formatted output
#include <iostream> // For cin, cout, and system
#include <string> // For string data type
using namespace std; // So "std::cout" may be abbreviated to "cout", for example.
string convertDecToBin(int dec)
{
int *arrayHex, arraySize = 0;
arrayHex = new int[];
string s = " ";
int r = dec;
for (int i = 0; r != 0; i++)
{
arrayHex[i] = r % 2;
r = r / 2;
arraySize++;
}
for (int j = 0; j < arraySize; j++)
{
s = s + to_string(arrayHex[arraySize - 1 - j]);
}
delete[] arrayHex;
return s;
}
string convertDecToOct(int dec)
{
int *arrayHex, arraySize = 0;
arrayHex = new int[];
string s = " ";
int r = dec;
for (int i = 0; r != 0; i++)
{
arrayHex[i] = r % 8;
r = r / 8;
arraySize++;
}
for (int j = 0; j < arraySize; j++)
{
s = s + to_string(arrayHex[arraySize - 1 - j]);
}
delete[] arrayHex;
return s;
}
int main()
{
int input = 0;
while (input != -1)
{
cout << "\nEnter a decimal number (-1 to exit loop): ";
cin >> input;
if (input != -1)
{
cout << "Your decimal number in binary expansion: " << convertDecToBin(input);
cout << "\nYour decimal number in octal ecpression: " << convertDecToOct(input);
}
}
cout << "\n\nPress any key to exit. . .";
_getch();
return 0;
}
arrayHex = new int[] is your problem - C\C++ does not support dynamic sizing arrays. You need to specify a size for the array to allocation, otherwise you'll get memory block overruns.
Using Bottom to up DP approach, I am able to solve the problem How to solve http://www.spoj.com/problems/MST1/ upto 10^8.
If input is very large n upto 10^9. I will not be able to create lookup table for upto 10^9. So what will be better approach to solve the problem ?
Is there any heuristic solution ?
#include <iostream>
#include <climits>
#include <algorithm>
using namespace std;
int main()
{
const int N_MAX = 20000001;
int *DP = new int[N_MAX];
DP[1] = 0;
for (int i = 2; i < N_MAX; i++) {
int minimum = DP[i - 1];
if (i % 3 == 0) minimum = min(minimum, DP[i/3]);
if (i % 2 == 0) minimum = min(minimum, DP[i/2]);
DP[i] = minimum + 1;
}
int T, N; cin >> T;
int c = 1;
while (T--) {
cin >> N;
cout << "Case " << c++ << ": " << DP[N] << endl;
}
delete[] DP;
}
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <vector>
using namespace std;
class TheNumberGameDivTwo{
private:
public:
string find( int n ){
string n1 = "John";
string n2 = "Brus";
//cout << "Mahesh"<< n2 << n1;
int i,q;
q = 0;
int k = n;
i = n-1;
for ( i = 2 ; i < k ; ++i ){
if ( !(k % i) ){
q += k / i;
k = k % i;
}
}
if ( q % 2 )
return "John";
else
return "Brus";
}
};
int main(){
TheNumberGameDivTwo T;
cout << endl << T.find(6);
cout << endl << "End of Program " << endl;
system("PAUSE");
}
Error 1
error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'std::string' (or there is no acceptable conversion)
d:\my documents\visual studio 2012\c++\topcoder\topcoder\source1.cpp 34 1 TopCoder
You are missing #include <string>
how do i avoid using pointer variables and pointer-based pass-by-reference in this program? as my instructor said there is no need to use pointers. This is a the tortoise and the hare simulator , you will use number generation to develop a simulation of this memorable event.
#include <iostream>
using std::cout;
using std::endl;
#include <cstdlib>
using std::rand;
using std::srand;
#include <ctime>
using std::time;
#include <iomanip>
using std::setw;
const int RACE_END = 70;
// prototypes
void moveTortoise( int *const );
void moveHare( int *const );
void printCurrentPositions( const int *const, const int *const );
int main()
{
int tortoise = 1;
int hare = 1;
int timer = 0;
srand( time( 0 ) );
cout << "ON YOUR MARK, GET SET\nBANG !!!!"
<< "\nAND THEY'RE OFF !!!!\n";
// loop through the events
while ( tortoise != RACE_END && hare != RACE_END )
{
moveTortoise( &tortoise );
moveHare( &hare );
printCurrentPositions( &tortoise, &hare );
timer++;
} // end loop
if ( tortoise >= hare )
cout << "\nTORTOISE WINS!!! YAY!!!\n";
else
cout << "\nHare wins. Yuch.\n";
cout << "\nTIME ELAPSED = " << timer << " seconds" << "\n" << endl;
system("pause");
return 0; // indicates successful termination
} // end main
// progress for the tortoise
void moveTortoise( int * const turtlePtr )
{
int x = 1 + rand() % 10; // random number 1-10
if ( x >= 1 && x <= 5 ) // fast plod
*turtlePtr += 3;
else if ( x == 6 || x == 7 ) // slip
*turtlePtr -= 6;
else // slow plod
++( *turtlePtr );
if ( *turtlePtr < 1 )
*turtlePtr = 1;
else if ( *turtlePtr > RACE_END )
*turtlePtr = RACE_END;
} // end function moveTortoise
// progress for the hare
void moveHare( int * const rabbitPtr )
{
int y = 1 + rand() % 10; // random number 1-10
if ( y == 3 || y == 4 ) // big hop
*rabbitPtr += 9;
else if ( y == 5 ) // big slip
*rabbitPtr -= 12;
else if ( y >= 6 && y <= 8 ) // small hop
++( *rabbitPtr );
else if ( y > 8 ) // small slip
*rabbitPtr -= 2;
if ( *rabbitPtr < 1 )
*rabbitPtr = 1;
else if ( *rabbitPtr > RACE_END )
*rabbitPtr = RACE_END;
} // end function moveHare
// display new position
void printCurrentPositions( const int * const snapperPtr,
const int * const bunnyPtr )
{
if ( *bunnyPtr == *snapperPtr )
cout << setw( *bunnyPtr ) << "OUCH!!!";
else if ( *bunnyPtr < *snapperPtr )
cout << setw( *bunnyPtr ) << 'H'
<< setw( *snapperPtr - *bunnyPtr ) << 'T';
else
cout << setw( *snapperPtr ) << 'T'
<< setw( *bunnyPtr - *snapperPtr ) << 'H';
cout << '\n';
} // end function printCurrentPositions
In C++ you can use references instead of pointers. For example, instead of
void foo(int *x) {
*x = *x + 1;
}
int main() {
int a = 0;
foo(&a);
return 0;
}
you can pass x by reference, like so:
void foo(int &x) {
x = x + 1;
}
int main() {
int a = 0;
foo(a);
return 0;
}
Passing a reference is sort of like passing a pointer, except you don't need to dereference the pointer every time you want to access the value it points to.
You can google "C++ pass by reference" for more information, such as this tutorial: http://www.learncpp.com/cpp-tutorial/73-passing-arguments-by-reference/
Alternatively, in your program, you could simply pass int arguments and return the new value:
int moveTortoise(int turtle) {
...
turtle = turtle + 3;
...
return turtle;
}
tortoise = moveTortoise(tortoise)
References& and pointers* are usefull when:
1. you deal with instances of complex classes that passing by reference is resource(CPU time & main memory) consuming operation;
2. when you want to change arguments what are passed(as any function in C++ can return only one value, opposit for ex. to python where multiply values can be returned, you can cope with that restriction by passing using & or *);
3. Other cases...
Built-in(atomic) types can be passed by value (which is you case) without decrease in efficiency.