Many people don't even realize how good C++ is until they come to know about it's Standard Template Library

This is the thread with some of the STL hacks that you should know

1. __gcd(a, b)

The method to find the gcd of two numbers is __gcd(a, b)

(Note: There are TWO underscores before the function name)

2. __builtin_popcount(a)

This method returns the number of 1s present in the binary notation of the number.

For eg : __builtin_popcount(4) = 1 (since 4b=100)

3. __builtin_ctz(a)

This method returns the number of trailing zeros of a number a.

This is also convenient in cases where you want the least significant bit of a number.

eg. __builtin_ctz(16) = 4

4. auto

auto for C++ is similar to the enhanced for loop of Java, except here we don’t need to even define the datatype of the iterator as it AUTOmatically gets defined

5. accumulate(arr.begin(), arr.end(), init)

This method the sum of all elements For eg :

vector<int> v{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};

int sum = std::accumulate(v.begin(), v.end(), 0);

cout<<sum // will print 55

6. iota(arr.begin(), arr.end(), val)

The final method on my list, is iota which populates an array/vector in increasing values starting from val

vector<int> a(10);
iota(a.begin(), a.end(), 2);

for(auto i:a)cout<<i<<" ";

// This outputs - 2 3 4 5 6 7 8 9 10 11