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---

CppIncrementOperator

---

(C++) ++ operator

The increment operator is used to raise an int's value by one.

Its opposite operator is the decrement operator, --.

include <cassert>


int i = 0;
++i;
assert(i==1);

Prefer ++i to i++ [1].

There are four ways to increment a value by 1:

1) i = i + 1;  
2) i += 1;
3) ++i;
4) i++;

When you define these 4 ways in a class then ways #1 and #3 produce a temporal copy of it, which might slow down your program unnecessarily. Therefore, #4 will be quicker of equally fast as #3.

Overloading the increment operator

struct MyInt
{
  //Prefix
  MyInt& operator++()
  {
    ++mX;         //Increment
    return *this; //Return class reference
  }
  //Postfix
  MyInt operator++(int)
  {
    MyInt old(*this); //Copy
    ++(*this);        //Increment original using prefix
    return old;       //Return old copy
  }
  int mX;
};
int main()
{
  MyInt m;
  ++m;
  m++;
}

'Increment operator' links

• C

Reference

• Bjarne Stroustrup. The C++ Programming Language. 2000. 3rd edition: ISBN: 0-201-88954-4. 2000. Item 19.5.7: 'Prefer ++p to p++'

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