Class member variable initializes with = operator??

[omkarchamphekar]

Output of the code is 25! How does the object of class opp initialize its private member?

#include<iostream>
using namespace std;

class constTest{
  
  private:
   int a;
  public:
   void show();
   constTest(int);
};
constTest::constTest(int m = 0)
{
  a = m;
}
void constTest::show(){cout<<a<<endl;}


int main()
{
  constTest opp(6*6);
  opp=5*5;
  opp.show();
  return 0;
}

[Cubbi]

Single-argument non-explicit constructors participate in implicit conversions: it is roughly equivalent to opp = constTest(5*5);

PS: put your default arguments on the declaration (inside the class); clang for example refuses to compile this as written.

[omkarchamphekar]

Thank Cubbi. And hence the explicit keyword!