C++ Random & Array - c++

Question

I try to use the random function for different things.
For now it works but I get one problem is I want to generate randomly the F in my code but they need to become array after. Also I need to use it and if I need to do it 1 by 1 I think my code will be too long and messy.
Do you know how I can do this?
#include <iostream>
#include <ctime>
#include <cstdlib>
using namespace std;
int main(){
srand(time(0));
//random numbers 1 to 10 for Time:
int t = rand() % 10 + 1 ;
cout << "There is "<< t << " Time;
int* F1 = new int [t];
int* F2 = new int [t];
int* F3 = new int [t];
int* F4 = new int [t];
int* F5 = new int [t];
cout << "Time per F: 0 Not available, 1 available;
//For F1
for(int i = 0; i < t; i++){
//random numbers 0 or 1:
F1[i] = rand() % 2 ;
}
cout << "The Time for F1 is ";
for(int a = 0; a < t; a++){
cout << " "<< F1[a] <<" ";
}
//For F2
for(int j = 0; j < t; j++){
//random numbers 0 or 1:
F2[j] = rand() % 2 ;
}
cout << "The Time slot for F2 is ";
for(int b = 0; b < t; b++){
cout << " "<< F2[b] << " ";
}
return 0;
}
Thank you
Edit: With the solution you give me helps to find the solution
I do int F[em][t];

Answer 1

Since you are using C++, and have access to the standard library, this could be written much cleaner as safer as a std::vector:
#include <iostream>
#include <ctime>
#include <cstdlib>
#include <iostream>
#include <vector>
using namespace std;
int main()
{
srand(time(0));
//Random number from 3 to 7
int numberOfVectors = (rand() % 7) + 3;
//Random number from 1 to 10.
int size = (rand() % 10) + 1;
std::cout << "There are " << numberOfVectors << " vectors." << std::endl;
std::cout << "Each vector has " << size << " elements." << std::endl;
std::vector< std::vector<int> > vectorOfVectorOfInt;
std::cout << "Value per element: 0 = Not available, 1 = available" << std::endl;
for(int vec = 0; vec < numberOfVectors; vec++)
{
//Create a new vector with 'size' elements.
std::vector<int> newVector(size);
for(int i = 0; i < size; i++)
{
//Generate a random value between 0 and 50
newVector[i] = (rand() % 50);
}
//Add the vector to our vector-of-vectors.
vectorOfVectorOfInt.push_back(newVector);
std::cout << "The values for Vector #" << (vec+1) << " is:";
for(int b = 0; b < size; b++)
{
int value = vectorOfVectorOfInt[vec][b];
std::cout << "\t" << value;
}
std::cout << std::endl;
}
return 0;
}
You can run it and see the results here: http://ideone.com/RWQhjO

Answer 2

Use an array of array:
#include <ctime>
#include <cstdlib>
using namespace std;
int main(){
srand(time(0));
//random numbers 1 to 10 for Time:
int t = rand() % 10 + 1 ;
cout << "Time per F: 0 Not available, 1 available";
const int f_num = 5;
cout << "There is "<< t << "Time";
int* F = new int*[f_num];
for(int i = 0; i < f_num; i++){
F[i] = new int[t];
cout << "The Time for F"<<i<<" is :";
for(int j = 0; j < t; j++){
//random numbers 0 or 1:
F[i][j] = rand() % 2 ;
cout << " "<< F1[i][j] <<" ";
}
}
}
BTW, your code is C-like. In C++, we usually use std::vector instead of plain array, and http://en.cppreference.com/w/cpp/numeric/random instead of rand() . Also, don't use using namespace std . This can cause name clashes.

Answer 3

I try to use the random function for different things.
Random things, presumably.
For now it works but I get one problem is I want to generate randomly the F in my code but they need to become array after.
You can generate this just as you generated your value for t.
const int number_of_fs = rand() % 10 + 1;
std::cout << "Working with " << number_of_fs << " Fs" << std::endl;
Also I need to use it and if I need to do it 1 by 1 I think my code will be too long and messy. Do you know how I can do this?
Your code is already too long and messy and has memory leaks. You should be using containers from the Standard Containers library, rather than pointers to pointers that never get deleted.
Here is how your code might look were you to use a std::map of std::vectors for instance:
#include <cstdlib>
#include <ctime>
#include <iostream>
#include <iterator>
#include <map>
#include <vector>
int main(){
srand(time(0));
//random numbers 1 to 10 for Time:
const int t = rand() % 10 + 1;
std::cout << "There is "<< t << " Time" << std::endl;
const int number_of_fs = rand() % 10 + 1;
std::cout << "Working with " << number_of_fs << " Fs" << std::endl;
std::map<int, std::vector<int> > f;
std::cout << "Time per F: 0 Not available, 1 available" << std::endl;
for (int f_slot = 1; f_slot <= number_of_fs; ++f_slot) {
for(int i = 0; i < t; i++){
//random numbers 0 or 1:
f[f_slot].push_back(rand() % 2);
}
std::cout << "The Time for F" << f_slot << " is " << std::endl;
std::copy(f[f_slot].begin(), f[f_slot].end(),
std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
}
}
See it run!
Population and printing of the contents of these containers should probably be extracted into separate functions, of course, but I didn't want to re-write your code completely.