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Diffstat (limited to 'c++.html.markdown')
| -rw-r--r-- | c++.html.markdown | 149 |
1 files changed, 144 insertions, 5 deletions
diff --git a/c++.html.markdown b/c++.html.markdown index a02e7e5b..5dc1af59 100644 --- a/c++.html.markdown +++ b/c++.html.markdown @@ -6,6 +6,8 @@ contributors: - ["Matt Kline", "https://github.com/mrkline"] - ["Geoff Liu", "http://geoffliu.me"] - ["Connor Waters", "http://github.com/connorwaters"] + - ["Ankush Goyal", "http://github.com/ankushg07"] + - ["Jatin Dhankhar", "https://github.com/jatindhankhar"] lang: en --- @@ -806,8 +808,8 @@ void doSomethingWithAFile(const std::string& filename) // have default comparators, but you can override it. class Foo { public: - int j; - Foo(int a) : j(a) {} + int j; + Foo(int a) : j(a) {} }; struct compareFunction { bool operator()(const Foo& a, const Foo& b) const { @@ -946,7 +948,7 @@ f1 = f2; #include<tuple> -// Conceptually, Tuples are similar to old data structures (C-like structs) but instead of having named data members , +// Conceptually, Tuples are similar to old data structures (C-like structs) but instead of having named data members, // its elements are accessed by their order in the tuple. // We start with constructing a tuple. @@ -956,10 +958,10 @@ const int maxN = 1e9; const int maxL = 15; auto second = make_tuple(maxN, maxL); -// printing elements of 'first' tuple +// Printing elements of 'first' tuple cout << get<0>(first) << " " << get<1>(first) << "\n"; //prints : 10 A -// printing elements of 'second' tuple +// Printing elements of 'second' tuple cout << get<0>(second) << " " << get<1>(second) << "\n"; // prints: 1000000000 15 // Unpacking tuple into variables @@ -985,6 +987,143 @@ cout << get<0>(concatenated_tuple) << "\n"; // prints: 10 cout << get<3>(concatenated_tuple) << "\n"; // prints: 15 cout << get<5>(concatenated_tuple) << "\n"; // prints: 'A' + +///////////////////// +// Containers +///////////////////// + +// Containers or the Standard Template Library are some predefined templates. +// They manage the storage space for its elements and provide +// member functions to access and manipulate them. + +// Few containers are as follows: + +// Vector (Dynamic array) +// Allow us to Define the Array or list of objects at run time +#include<vector> +vector<Data_Type> Vector_name; // used to initialize the vector +cin >> val; +Vector_name.push_back(val); // will push the value of variable into array + +// To iterate through vector, we have 2 choices: +// Normal looping +for(int i=0; i<Vector_name.size(); i++) +// It will iterate through the vector from index '0' till last index + +// Iterator +vector<Data_Type>::iterator it; // initialize the iteartor for vector +for(it=vector_name.begin(); it!=vector_name.end();++it) + +// For accessing the element of the vector +// Operator [] +var = vector_name[index]; // Will assign value at that index to var + + +// Set +// Sets are containers that store unique elements following a specific order. +// Set is a very useful container to store unique values in sorted order +// without any other functions or code. + +#include<set> +set<int> ST; // Will initialize the set of int data type +ST.insert(30); // Will insert the value 30 in set ST +ST.insert(10); // Will insert the value 10 in set ST +ST.insert(20); // Will insert the value 20 in set ST +ST.insert(30); // Will insert the value 30 in set ST +// Now elements of sets are as follows +// 10 20 30 + +// To erase an element +ST.erase(20); // Will erase element with value 20 +// Set ST: 10 30 +// To iterate through Set we use iterators +set<int>::iterator it; +for(it=ST.begin();it<ST.end();it++) { + cout << *it << endl; +} +// Output: +// 10 +// 30 + +// To clear the complete container we use Container_name.clear() +ST.clear(); +cout << ST.size(); // will print the size of set ST +// Output: 0 + +// NOTE: for duplicate elements we can use multiset + +// Map +// Maps store elements formed by a combination of a key value +// and a mapped value, following a specific order. + +#include<map> +map<char, int> mymap; // Will initalize the map with key as char and value as int + +mymap.insert(pair<char,int>('A',1)); +// Will insert value 1 for key A +mymap.insert(pair<char,int>('Z',26)); +// Will insert value 26 for key Z + +// To iterate +map<char,int>::iterator it; +for (it=mymap.begin(); it!=mymap.end(); ++it) + std::cout << it->first << "->" << it->second << '\n'; +// Output: +// A->1 +// Z->26 + +// To find the value correponsing to a key +it = mymap.find('Z'); +cout << it->second; + +// Output: 26 + + +/////////////////////////////////// +// Logical and Bitwise operators +////////////////////////////////// + +// Most of the operators in C++ are same as in other languages + +// Logical operators + +// C++ uses Short-circuit evaluation for boolean expressions, i.e, the second argument is executed or +// evaluated only if the first argument does not suffice to determine the value of the expression + +true && false // Performs **logical and** to yield false +true || false // Performs **logical or** to yield true +! true // Performs **logical not** to yield false + +// Instead of using symbols equivalent keywords can be used +true and false // Performs **logical and** to yield false +true or false // Performs **logical or** to yield true +not true // Performs **logical not** to yield false + +// Bitwise operators + +// **<<** Left Shift Operator +// << shifts bits to the left +4 << 1 // Shifts bits of 4 to left by 1 to give 8 +// x << n can be thought as x * 2^n + + +// **>>** Right Shift Operator +// >> shifts bits to the right +4 >> 1 // Shifts bits of 4 to right by 1 to give 2 +// x >> n can be thought as x / 2^n + +~4 // Performs a bitwise not +4 | 3 // Performs bitwise or +4 & 3 // Performs bitwise and +4 ^ 3 // Performs bitwise xor + +// Equivalent keywords are +compl 4 // Performs a bitwise not +4 bitor 3 // Performs bitwise or +4 bitand 3 // Performs bitwise and +4 xor 3 // Performs bitwise xor + + ``` Further Reading: |