Some minor (mostly stylistic) fixes in C++

This commit is contained in:
Valery Cherepanov 2016-08-02 16:32:38 +03:00 committed by GitHub
parent 50c8f7b4dd
commit 47679dfcbe

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@ -808,8 +808,8 @@ void doSomethingWithAFile(const std::string& filename)
// have default comparators, but you can override it. // have default comparators, but you can override it.
class Foo { class Foo {
public: public:
int j; int j;
Foo(int a) : j(a) {} Foo(int a) : j(a) {}
}; };
struct compareFunction { struct compareFunction {
bool operator()(const Foo& a, const Foo& b) const { bool operator()(const Foo& a, const Foo& b) const {
@ -948,7 +948,7 @@ f1 = f2;
#include<tuple> #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. // its elements are accessed by their order in the tuple.
// We start with constructing a tuple. // We start with constructing a tuple.
@ -958,10 +958,10 @@ const int maxN = 1e9;
const int maxL = 15; const int maxL = 15;
auto second = make_tuple(maxN, maxL); 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 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 cout << get<0>(second) << " " << get<1>(second) << "\n"; // prints: 1000000000 15
// Unpacking tuple into variables // Unpacking tuple into variables
@ -989,43 +989,43 @@ cout << get<5>(concatenated_tuple) << "\n"; // prints: 'A'
///////////////////// /////////////////////
// CONTAINERS // Containers
///////////////////// /////////////////////
// Containers or the Standard Template Library are some predefined templates // Containers or the Standard Template Library are some predefined templates.
// They manages the storage space for its elements and provide // They manage the storage space for its elements and provide
// member functions to access and manipulate them // member functions to access and manipulate them.
// Few containers are as follows:- // Few containers are as follows:
// Vectors (Dynamic arrays) // Vector (Dynamic array)
// Allow us to Define the Array or list of objects at run time // Allow us to Define the Array or list of objects at run time
#include<vector> // will include the header file for vector #include<vector>
vector< Data_Type > Vector_name; // used to initialize the vector vector<Data_Type> Vector_name; // used to initialize the vector
cin>>val; cin >> val;
Vector_name.push_back(val); // will push the value of variable into array Vector_name.push_back(val); // will push the value of variable into array
// To iterate through vector, we have 2 choices // To iterate through vector, we have 2 choices:
// using normal looping // Normal looping
for(int i=0; i<Vector_name.size(); i++) for(int i=0; i<Vector_name.size(); i++)
// It will iterate through the vector from index '0' till last index // It will iterate through the vector from index '0' till last index
// Using Iterator // Iterator
vector<Data_Type>::iterator it; // initialize the iteartor for vector vector<Data_Type>::iterator it; // initialize the iteartor for vector
for(it=vector_name.begin(); it!=vector_name.end();++it) for(it=vector_name.begin(); it!=vector_name.end();++it)
// For accessing the element of the vector // For accessing the element of the vector
// Operator [] // Operator []
var= vector_name[index]; //will assign value at that index to var var = vector_name[index]; // Will assign value at that index to var
// Set // Set
// Sets are containers that store unique elements following a specific order // Sets are containers that store unique elements following a specific order.
// Very useful container to store unique values in sorted order // Set is a very useful container to store unique values in sorted order
// without any other functions or code // without any other functions or code.
#include<set> // Will include the header file for sets #include<set>
set< int > ST; // Will initialize the set of int data type set<int> ST; // Will initialize the set of int data type
ST.insert(30); // Will insert the value 30 in set ST ST.insert(30); // Will insert the value 30 in set ST
ST.insert(10); // Will insert the value 10 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(20); // Will insert the value 20 in set ST
@ -1037,47 +1037,47 @@ ST.insert(30); // Will insert the value 30 in set ST
ST.erase(20); // Will erase element with value 20 ST.erase(20); // Will erase element with value 20
// Set ST: 10 30 // Set ST: 10 30
// To iterate through Set we use iterators // To iterate through Set we use iterators
set< int >::iterator it; set<int>::iterator it;
for(it=ST.begin();it<ST.end();it++) for(it=ST.begin();it<ST.end();it++) {
{ cout << *it << endl;
cout<<*it<<endl;
} }
// OUTPUT: // Output:
// 10 // 10
// 30 // 30
// To clear the complete container we use Container_name.clear() // To clear the complete container we use Container_name.clear()
ST.clear(); ST.clear();
cout<<ST.size(); // will print the size of set ST cout << ST.size(); // will print the size of set ST
// OUTPUT: 0 // Output: 0
// NOTE: for duplicate elements we can use multiset // NOTE: for duplicate elements we can use multiset
// MAP // Map
// Maps store elements formed by a combination of a key value // Maps store elements formed by a combination of a key value
// and a mapped value, following a specific order // and a mapped value, following a specific order.
#include<map> // Will include the header file for map #include<map>
map< char, int >mymap; // Will initalize the map with key as char and value as int map<char, int> mymap; // Will initalize the map with key as char and value as int
mymap.insert ( pair<char,int>('A',1) ); mymap.insert(pair<char,int>('A',1));
// Will insert value 1 for key A // Will insert value 1 for key A
mymap.insert ( pair<char,int>('Z',26) ); mymap.insert(pair<char,int>('Z',26));
// Will insert value 26 for key Z // Will insert value 26 for key Z
// To iterate // To iterate
map<char,int>::iterator it; map<char,int>::iterator it;
for (it=mymap.begin(); it!=mymap.end(); ++it) for (it=mymap.begin(); it!=mymap.end(); ++it)
std::cout << it->first << "->" << it->second <<'\n'; std::cout << it->first << "->" << it->second << '\n';
// Output: // Output:
// A->1 // A->1
// Z->26 // Z->26
// To find the value correponsing to a key // To find the value correponsing to a key
it = mymap.find('Z'); it = mymap.find('Z');
cout<<it->second; cout << it->second;
// Output: 26
// OUTPUT: 26
/////////////////////////////////// ///////////////////////////////////
// Logical and Bitwise operators // Logical and Bitwise operators
@ -1087,17 +1087,17 @@ cout<<it->second;
// Logical operators // Logical operators
// C++ uses Short - circuit evaluation for boolean expressions, i.e, the second argument is executed or // 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 // 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 and** to yield false
true || false // Performs **logical or** to yield true true || false // Performs **logical or** to yield true
! true // Performs **logcical not** to yield ! true // Performs **logical not** to yield false
// Instead of using symbols equivalent keywords can be used // Instead of using symbols equivalent keywords can be used
true and false // Performs **logical and** to yield false true and false // Performs **logical and** to yield false
true or false // Performs **logical or** to yield true true or false // Performs **logical or** to yield true
not true // Performs **logcical not** to yield not true // Performs **logical not** to yield false
// Bitwise operators // Bitwise operators
@ -1108,20 +1108,20 @@ not true // Performs **logcical not** to yield
// **>>** Right Shift Operator // **>>** Right Shift Operator
// << shifts bits to the right // >> shifts bits to the right
4 >> 1 // Shifts bits of 4 to right by 1 to give 2 4 >> 1 // Shifts bits of 4 to right by 1 to give 2
// x << n can be thought as x / 2^n // x >> n can be thought as x / 2^n
~4 // Performs a bitwise not ~4 // Performs a bitwise not
4 | 3 // Performs bitwise or 4 | 3 // Performs bitwise or
4 & 3 // Performs bitwise and 4 & 3 // Performs bitwise and
4 ^ 3 // Performs bitwise xor 4 ^ 3 // Performs bitwise xor
// Equivalent keywords are // Equivalent keywords are
compl 4 // Performs a bitwise not compl 4 // Performs a bitwise not
4 bitor 3 // Performs bitwise or 4 bitor 3 // Performs bitwise or
4 bitand 3 // Performs bitwise and 4 bitand 3 // Performs bitwise and
4 xor 3 // Performs bitwise xor 4 xor 3 // Performs bitwise xor
``` ```