/* C++ program to create, write and read from data file using class fstream */ #include "iostream" #include "fstream" // required using namespace std; int main(){ /* Block to write to file */ fstream fileOb; fileOb.open("MyFile", ios::out | ios::in); if(fileOb.is_open()){ cout<<"\nSuccess .."<<endl; fileOb<<"First Line added to file. \n"; // operator << have been overloaded for putting contents into file fileOb<<"Second line added. \n"; fileOb<<"Third line added. \n"; //fileOb.close(); // close the file }else{ cout<<"\nFile creation and opening failed .. "<<endl; }
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Showing posts with label CPP. Show all posts
Showing posts with label CPP. Show all posts
Thursday, 21 September 2017
C++ program to create, write and read from data file using class fstream
C++ program to add user defined contents to file and to read the file later
/* C++ program to add user defined contents to file and to read the file later */ #include "iostream" #include "fstream" // required using namespace std; int main(){ /* Block to write user-defined contents to file */ int count, age; string name; ofstream outFile; outFile.open("MyFile", ios::out); // writing ios::out is optional as object used is outFile if(outFile.is_open()){ cout<<"\nSuccess .."<<endl; cout<<"\nHow many entries do you wish to add to file: "; cin>>count; for(int i=0; i<count; i++){ cout<<"\nEnter name: "; cin>>name; cout<<"\nEnter age: "; cin>>age; outFile<<name<<"\t"<<age<<endl; // adding contents to file }
C++ program to create, write and read from data file
/* C++ program to create, write and read from data file */ #include "iostream" #include "fstream" // required using namespace std; int main(){ /* Block to write to file */ ofstream outFile; outFile.open("MyFile", ios::out); // writing ios::out is optional as object used is outFile if(outFile.is_open()){ cout<<"\nSuccess .."<<endl; outFile<<"First Line added to file. \n"; // operator << have been overloaded for putting contents into file outFile<<"Second line even added. \n"; outFile.close(); // close the file }else{ cout<<"\nFile creation and opening failed .. "<<endl; }
Class templates having single level inheritance in C++
/* Class templates having single level inheritance */ #include "iostream" using namespace std; template <class T> class First{ T x; public: void getFirst(T a){ x = a; } void showFirst(){ cout<<"\nx: "<<x<<endl; } }; template <class T2> class Second: public First<T2>{ T2 y, z; public: Second(T2 m, T2 n){ y = m; z = n; } void showAll(){ // display(); cout<<"\ny: "<<y<<"\tz: "<<z<<endl; } };
Class template having function template definition outside class in C++
/* Class template having function template definition Note: If you write showData() definition outside class in normal way, means without template then age and name wont be accessible. thats the reason showData() is defined inside. */ #include "iostream" using namespace std; template <class T1, class T2> class Person{ T1 age; T2 name; public: void getData(); void showData(){ cout<<"\nage: "<<age<<"\tname: "<<name<<endl; } }; template <class T1, class T2> void Person<T1,T2>:: getData(){ cin>>age>>name; }
Simple class template having simple function template in C++
/* Simple class template having simple function template */ #include "iostream" using namespace std; template <class T> class Person{ T age; public: void getData(T a){ age = a; } T showData(); };
Class template having default and parameterized constructors in C++
/* Class template having default and parameterized constructors */ #include "iostream" using namespace std; template <typename T1, class T2> class Person{ T1 age; T2 name; public: Person(){ age = 32; name = "Pavan"; } Person(T1 x, T2 y){ age = x; name = y; } void display(){ cout<<"\nAge: "<<age<<"\tname: "<<name<<endl; } };
Class template in C++ to accept and display person details
/* Class template which have data members of different types */ #include "iostream" using namespace std; template <class T1, typename T2> class Person{ T1 age; T2 name; public: void getData(){ cout<<"\nEnter age & name "; cin>>age>>name; } void showData(){ cout<<"\nage: "<<age<<"\tname: "<<name<<endl; } };
Function template with two generic types in C++
/* Function template with two generic types */ #include "iostream" using namespace std; template <class T1, class T2> void display(T1 xx, T2 yy){ cout<<endl<<xx<<" "<<yy; }
Function template to swap two numbers in C++
/* Demonstrating function template */ #include "iostream" using namespace std; template <class T> void swaparg(T &a, T &b){ T temp; temp = a; a = b; b = temp; }
Function template to check max numebr in C++
/* Function template demo to check max number in c++ */ #include "iostream" using namespace std; template <typename T> T getMax(T x, T y){ return (x>y?x:y); } int main(){ cout<<"Max No: "<< getMax <int> (4,5)<<endl; return 0; } /* OUTPUT [pavan@localhost Template]$ g++ FunctionTemplate.cpp [pavan@localhost Template]$ ./a.out Max No: 5 [pavan@localhost Template]$ */
Smart pointer in C++
/* Smart pointer demonstration -- smart pointer as name suggest works smart. -- In case of normal pointer, delete is expected to be called explicitley. -- In case pf smart pointer, destruction happens automatically even though some exception occurs */ #include "iostream" using namespace std; class Person{ int age; char *name; public: Person():age(0),name(0){ } Person(int age, char* name):age(age), name(name){ } ~Person(){ } void display(){ cout<<"\nAge: "<<age<<"\t"<<name<<endl; } };
New and delete in C++
/* New Delete Demo in C++ */ #include "iostream" #include <new> // Some time you may have to include this file using namespace std; int main(){ int *var = new int(10); //allocating single block of memory and initializing there only cout<<"\nVar: "<<*var; *var = 50; cout<<"\nVar: "<<*var; cout<<endl;
Pointer to obejct with dynamic memory allocation in C++
/* Pointer to object with dynamic memory allocation */ #include "iostream" using namespace std; class Box{ public: Box(){ cout<<"\nConstructor called.."; } ~Box(){ cout<<"\nDestructor called.."<<endl; } };
Array of pointers to charecter in C++
/* Array of poniters to character */ #include "iostream" using namespace std; const int MAX=3; int main(){ char *name[MAX] = { "Pavan", "Jaiswal", "Pune" }; cout<<"\n Printing character array elements \n"; for(int i=0; i<MAX; i++){ cout<<" "<<name[i]; // *name[i] prints first character of each string, say P J P } cout<<endl; return 0; }
Array of pointers in C++
/* Array of pointers in C++ */ #include "iostream" using namespace std; const int MAX=3; int main(){ int var[MAX] = {10,20,30}; int *ptr[MAX]; cout<<"\nPrinting Array elements \n"; for(int i=0; i<MAX; i++) cout<<" "<<var[i]; cout<<endl;
Function pointer used to do bubble sort in C++
/* Function Pointer used for bubble sort */ #include "iostream" using namespace std; int compare(int i, int j){ if(i>j) return 1; else return -1; }
Basic demo of function pointer for callback purpose in C++
/*
Basic demo of function pointer for callback purpose
*/
#include "iostream"
using namespace std;
void meaningOfLife(){
cout<<"\nHi"<<endl;
}
void printANumber(int num, void (*ptr)()){
cout<<"\nnum: "<<num;
(*ptr)(); // simply ptr();
}
Basic demo of function pointer for callback purpose
*/
#include "iostream"
using namespace std;
void meaningOfLife(){
cout<<"\nHi"<<endl;
}
void printANumber(int num, void (*ptr)()){
cout<<"\nnum: "<<num;
(*ptr)(); // simply ptr();
}
Function pointer in C++
/* Demonstrating function pointer that takes two int args and return back int value */ #include "iostream" using namespace std; void printHello(){ cout<<endl<<"Hello All"<<endl; }
Add and display data to array using pointer notation
/* Insert and display data entered using pointer notation */ #include "iostream" using namespace std; int main(){ int arr[5]; cout<<"\nEnter 5 elements \n"; for(int i=0; i<5; i++){ cin>>*(arr+i); } cout<<"\n\nPrinting Array elements"; for(int i=0; i<5; i++){ cout<<"\n"<<*(arr+i); }
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