Differences between Java and C++

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Original post by EmrldDrgn I'm not looking for the things that are called out in the numerous "Java for C++ Developers" tutorials on the net, just stumbling blocks that have been encountered by real-world people.

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Original post by WhatsUnderThere Coding in java is nothing more than writing atrocious C++ code. 1. It encourages the use of 'new' without any considerations. Obviously, no 'delete's are necessary because of the garbage collection, but in C++, using heap memory is something you would typically want to avoid when you can use the stack. 2. There is no 'const'. This is one of the greatest features of C++. 3. Java templates are basically a poor hack of the C++ version. 4. All objects are automagically treated as references. 5. No operator overloading. As far as pitfalls go, just be sure to bring a nose plug. When coding in java, you may find a hideous stench rising from your keyboard.

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Original post by WhatsUnderThere 1. It encourages the use of 'new' without any considerations. Obviously, no 'delete's are necessary because of the garbage collection, but in C++, using heap memory is something you would typically want to avoid when you can use the stack.

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3. Java templates are basically a poor hack of the C++ version.

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Original post by godsenddeath 1. there is the final keyword, same thing

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2. their templates are pretty much the same, just called generics instead.

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Original post by godsenddeath this sounds like someone who has no meaningful experience in java.

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1. there is the final keyword, same thing

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2. their templates are pretty much the same, just called generics instead.

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4. yeah, i wish java let you overload operators, but thats hardly a huge reason to hate it.

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all this being said, I am a C++ programmer, and I do prefer using C++. I know java because I'm in school

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Original post by ToohrVyk Quote: Original post by godsenddeath 1. there is the final keyword, same thing Nope. In C++, a const variable prevents you from altering the object represented by the variable (this forbids calling non-const methods, among other things), whereas in Java, a final variable prevents you from assigning to the variable more than once (this allows calling any kind of method afterwards). There is no way in Java to specify "You Shall Not Modify This Object", unlike in C++.

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Original post by someboddy Quote: Original post by ToohrVyk Quote: Original post by godsenddeath 1. there is the final keyword, same thing Nope. In C++, a const variable prevents you from altering the object represented by the variable (this forbids calling non-const methods, among other things), whereas in Java, a final variable prevents you from assigning to the variable more than once (this allows calling any kind of method afterwards). There is no way in Java to specify "You Shall Not Modify This Object", unlike in C++. Don't forget that if you declare a const pointer in C++ you can still modify the referred object(or primitive\struct\array).

int main () {    int foo = 42;    int* pfoo = &foo    *pfoo = 42; // okay    int const* const_pfoo = &foo    *const_pfoo = 42; // "error: assignment of read-only location"    int *const pfoo_const = &foo    *pfoo_const = 42; // okay    int const* const const_pfoo_const = &foo    *const_pfoo_const = 42; // "error: assignment of read-only location"    int * unconst_pfoo = const_pfoo; // "error: invalid conversion from `const int*' to `int*'"    int * static_cast_unconst_pfoo = static_cast <int*> (const_pfoo); // "error: invalid static_cast from `const int*' to `int*'"    int * const_cast_unconst_pfoo = const_cast <int*> (const_pfoo); // okay    *const_cast_unconst_pfoo = 42; // undefined behaviour if referencee would be const    int &rfoo = foo;    rfoo = 42; // okay    int const &const_rfoo = foo;    const_rfoo = 42; // "error: assignment of read-only reference `const_rfoo'"    int &unconst_rfoo = const_cast <int&> (const_rfoo); // okay    unconst_rfoo = 42; // undefined behaviour if referencee would be const}

int main () {    struct X { int x; };    X x = { 42 };    X const& const_rx = x;    const_rx.x = 42;  // error: assignment of data-member `main()::X::x' in read-only structure    struct Y { mutable int y; };    Y y = { 42 };    Y const& const_ry = y;    const_ry.y = 42;  // okay}

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Original post by phresnel int foo = 42;int const* const_pfoo = &fooint * const_cast_unconst_pfoo = const_cast <int*> (const_pfoo); // okay*const_cast_unconst_pfoo = 42; // epic fail: undefined behaviour

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Original post by ToohrVyk Quote: Original post by phresnel int foo = 42;int const* const_pfoo = &fooint * const_cast_unconst_pfoo = const_cast <int*> (const_pfoo); // okay*const_cast_unconst_pfoo = 42; // epic fail: undefined behaviour The behaviour is defined, as per the standard (7.1.5.1 §5). The basic idea is that foo is a non-const integer, and can therefore be modified through non-const references, which the const_cast allows you to build. Of course, if foo was a const integer, then this would be indeed undefined.

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Original post by phresnel Is there any way of getting a copy of that paragraph?

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-5- [Example: const int ci = 3; // cv-qualified (initialized as required) ci = 4; // ill-formed: attempt to modify const int i = 2; // not cv-qualified const int* cip; // pointer to const int cip = &i // OK: cv-qualified access path to unqualified *cip = 4; // ill-formed: attempt to modify through ptr to const int* ip; ip = const_cast(cip); // cast needed to convert const int* to int* *ip = 4; // defined: *ip points to i, a non-const object const int* ciq = new const int (3); // initialized as required int* iq = const_cast(ciq); // cast required *iq = 4; // undefined: modifies a const object

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Original post by WhatsUnderThere 2. There is no 'const'. This is one of the greatest features of C++.

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Original post by ToohrVyk You can look for the standard draft online.

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Original post by EmrldDrgn P.S. I also have some C# knowledge. I've heard they're similar?