How to make multiple instances of a class in C++ - c++

Question

How do you create multiple class instances without individually typing in their names?
int main(){
myClass myInstance_1;
myClass myInstance_2;
myClass myInstance_3;
...
myClass myInstace_10;
}

Answer 1

You may do the following:
int main(){
std::vector<myClass> myInstances;
for(int i = 0; i < 10; ++i) {
myInstances.emplace_back(i);
}
myInstances[5].myClassFunction();
}

Answer 2

How do you create multiple class instances without individually typing in their names?
The answer is you make an array, but not the way you tried it.
Like this:
int main()
{
MyClass myInstance[10];
for(int i = 0; i < 10; i++)
{
myInstance[i].myClassFunction();
}
}
TIP: Don't use arrays, use std::vector or std::array.
(see answer from #Jarod42)

Answer 3

Solution 1: Use an array of integers as an initializer, the constructor is used to convert the integer to myClass.
class myClass
{
public:
//constructor
myClass( int num) {m_number = num;};
void myClassFunction(){cout<< "I am " << m_number << endl;}
private:
int m_number;
};
int main(){
myClass myInstance[10] = {0,1,2,3,4,5,6,7,8,9};
for ( int i=0; i< 10; i++) myInstance[i].myClassFunction();
}
Solution 2: Use a static counter to set m_number, so no need to use a non-default constructor.
class myClass
{
public:
//constructor
myClass(){m_number=counter++;};
void myClassFunction(){cout<< "I am " << m_number << endl;}
private:
int m_number;
static int counter;
};
int myClass::counter = 0;
int main(){
myClass myInstance[10];
for ( int i=0; i< 10; i++) myInstance[i].myClassFunction();
}
Solution 3: Set the m_number after the constructor call, so the default constructor is enough.
class myClass
{
public:
//constructor
void setNum(int num){m_number=num;};
void myClassFunction(){cout<< "I am " << m_number << endl;}
private:
int m_number;
};
int main(){
myClass myInstance[10];
for ( int i=0; i< 10; i++) myInstance[i].setNum(i);
for ( int i=0; i< 10; i++) myInstance[i].myClassFunction();
}

Answer 4

Just like Jarod42's code:
int main(){
std::vector<myClass> myInstances;
for(int i = 0; i < 10; ++i) {
myInstances.push_back(myClass(i));
}
myInstances[5].myClassFunction();
}
I think these should work.

Answer 5

Use array:
myClass myInstance[10];
This will create an array with 10 instances but each instance will have its m_number set to 0.
Another approach:
myClass *myInstance = new myClass[10];
for (unsigned int i = 0; i < 10; i++)
{
myInstance[i] = new myClass(i);
}
Here each instance will have different m_number values
Edit for the sake of fixing the problem with above code. Better solutions have already been proposed.
myClass *myInstance[10];
// Allocate
for (unsigned int i = 0; i < 10; i++)
{
myInstance[i] = new myClass(i);
}
// At the end free
for (unsigned int i = 0; i < 10; i++)
{
delete myInstance[i];
}