Programs in C & C++ with Example

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There seems to be a confusion among people (even authors of Many books) about ways of passing values to a function. Question: How many ways are there to pass a variable to a function in C ? Ans: proposed by most people (authors) : Passing variables by values Passing variables by references My Reaction : Wrong !!!!!!! To make thing even worse, the example most writer put up for passing values by references is this :   #include<stdio.> void swap (int *x, int *y) { int* t; *t=*x; *x=*y; *y=*t; } int main () { int x,y; x=100; y=200; swap(&x,&y); printf("%d,%d",x,y); } I don't know if you get this example or not, But this example is wrong. This example is using pointers , and pointers are not references. So again: Question: How many ways are actually there to pass variables to functions in C ? Well there is only one way: Passing variables by value. Question: But What about books claiming that vari...

This is a Program for Linked List using C. The Code contains enough comments to make your life easy. # include < stdio.h > // structure to hold our data // we call it node // has a int 'value' // also has a pointer that points to next node struct node { int value ; struct node * next ; } ; //typdef will save our time //from now onwards 'struct node' will be replaced by NODE typedef struct node NODE ; // you can notice that we are passing NODE** to insert // Why???? // The answer is simple // since we will be passing the head pointer to the function // and head pointer can be modified in insertion operation // so we must pass a NODE** // reason being if we pass a NODE* to function // its value will be restored after function has returned // hence even if have modified head pointer, it will be restored // so we pass NODE** //------------------ // v is the value to be inserted void insert ( NODE * * base , int v ) {...

Constructor play an important part in c++. They can initialize the values of a given object to some known values. This is important as constructor will be able to set some values in objects which otherwise may have some garbage values. Most uninitialized value in objects are main cause of the bugs. But the concept of constructor can allow us to do just anything beside initializing values. Constructor are always called when an object is created. This property of constructor is very useful in situation when you need to perform some task as soon as an object is created. So constructor is a special function that gets called automatically when an object is created. This function can like any other function do anything (like initializing values). Overloading Constructor : This process is very similar to the overloading of simple functions. Since constructor are also function , they can be overloaded like any other functions. This allows user to create many constructor, which can help u...

Here is an example of Bubble sort in C++.  The example will perform bubble sort on a set of 10 integers. The example is a OO example . So everything is in a class called bubble. The class it self has following methods in it.

Finding Armstrong number is again a great exercise for students The exercise involves clever use of modulus operator to extract the digits and then using those digits to perform calculations.

In this Example I will demonstrate overloading a unary operator. The overloading is done in similar way as we did for binary operator. In this example I will be using a Vector Class. The operator we are going to over load is the unary "~" (tilde) operator. although you can use any unary overloadable operator. Method: In this example the overloaded operator will be the part of the class i.e. the over loaded definition will be a member function. (As we know overloading can be done using non member functions too). So the unary operator will not have any arguments in it. We will overload ~ operator so that it will reflect the vector so that its z component becomes x component and vice versa. So input vector will be 2i+3j+5k and its output vector will be 5i+3j+2k. although you can do anything you like. Code: # include < iostream > using namespace std ; class vector { int x , y , z ;      public : vector ( ) { x = y = z = 0 ; ...

Counting words in a String using C: This is very good exercise to test new programmers pointer skills. The task is to count the words in a given string using C. Well there might be many ways you can do it, I will demonstrate mine way. Note that mine solution might not be the optimal one, but it gets the job done.

Operator overloading using friend functions: Operators can be overloaded in c++ with friend functions also. The procedure is same as we discussed earlier. Here I will demonstrate operator overloading with "+" operator which is a binary operator. I will be using a complex number class (called complex). The class will have 2 data types, real and imaginary. Operator overloading will not be a part of class complex, but we will declare that this function is a friend of class complex.

c++ program to find prime numbers: The problem of finding prime number can be solved by checking all numbers, testing them for prime and then moving ahead. If you want to calculate nth prime. Then this can be done in a brutal way by checking the number one by one. This may sound odd, by there is no easy way then this  for prime numbers (Well Actually there are like Pollard's Rho Algorithm, Number Sieves or Shor's Quantum Algorithm, but we are talking about the one that most people may understand easily). There may be way to pre-calculate the prime numbers but that again is not sufficient. So how can we use c++ to create a program to find prime numbers.

Program for Multi Level Inheritance and Function Overriding: Function overriding is a very key programming feature in OOP system. This allows programmers to create objects which has similar function ( with same name) but having different implementations. Such technique is really helpful in situations where each object has a common function but implementations ( games for example).

I have updated my codes to now have color highlighting, This will make code look a little better :) Cheers

Program for Matrix Multiplication in C++ using Operator Overloading : We will now try to multiply two matrix by using the concept of operator overloading. The described way is very very easy to understand. We will be overloading "*" operator for this purpose. Although this can be done by any binary operator.

Stack in C : Stack is a very useful data structure in C, It is used in many situations. Implementing stack can be done using a global array and a global pointer of the stack. although this implementation reveals how good OOP is for such situations. There will be three basic functions of the stack. One will be push() operation, which will push the given element to the stack. Pop() function  will pop out the element from the top. A show function to show the content of the stack.

Ask any new computer science student ," What is the most dreaded topic in C language ?". They will reply ," Still having nightmares about pointers !!!". And I don't blame them. In fact pointers become even more dreaded as the learning curve is really steep for beginner. So what makes pointers so "evil" ? I personally think its not the pointers but its lack of knowledge about memory that actually kills a new student. Hence I claim " Pointers are innocent ".

What are Contructors in C++? Ans: Constructor are special function that can help initialize an object. Do we really need contructors in C++? Well, Its a good feature and really helps programmer. I am a good programmer and I don't Need contructors. LOL !!!!! Ok enough of chit chat, lets get to the point. Why contructors were included in C++. The answer lies in very nature of programmers. Programmer frequently get messy with code and allow mistakes to happen ( LOL :P). How? Lets have a look on following code : #include<iostream> using namespace std; int main() { int k; cout<<k; } This is a classical example of programmer forgetting to initialize the variable. Hence causing unexpected errors. This problem gets more complicated as we start creating objects. Since objects may have many data, its a very common mistake to forget to initialize the data portions of objects. This is where construcors come handy. The contructors have a property that they get called aut...

Objective : Using python calculate factorial of a number. Logic : the logic is exactly the same as we do it in C language. so we use loops. Code: def factorial ( number ) : ans = 1 ; for i in range ( 2 , number + 1 ) : ans = ans * i ; print ( ans ) return What are the benefits of this code in python over the same in C? well on the first you won't see much advantages, but that's where you overlook Python !!! Python utilizes a heavy bit integers (128 bit integers), so 200! can be easily calculated without using decimal representation. Isn't that cool !!!

Objective : To check if given number is palindrome or not in C. Programming logic : This is a very easy program if you know how to reverse a number. Once you have found the reverse of number just compare it with original, if both are same then the number is palindrome. Code: # include < stdio.h > int main ( ) { int k ; printf ( " \n enter number = " ) ; scanf ( " %d " , & k ) ; if ( palindrome ( k ) ) { printf ( " \n The number is palindrome " ) ; } else { printf ( " \n The number is not palindrome " ) ; } return ( 0 ) ; } int palindrome ( int x ) { int rev = 0 ; //to calculate reverse of number int k = x ; while ( k > 0 ) { rev = rev * 10 + k % 10 ; k = k / 10 ; } if ( x = = rev ) // check if reverse is equal to given number { return ( 1 ) ; //if yes then return 1 } else ...

Objective : To print given numbers of Fibonacci series. (1,1,2,3,5.....) non recursively. Programming Logic : Its easy to print the above Fibonacci series in C. the number is always sum of previous 2 terms. This series starts with numbers 1,1. so next term is 1+1=2. Then next term is 1+2=3 and so on. (It may be noted that series 1,3,4,7,11,18.... is also a Fibonacci series, but it starts with 1,3 ) Code : # include < stdio.h > int main ( ) { int k ; printf ( " \n enter number of terms to print= " ) ; scanf ( " %d " , & k ) ; fic ( k ) ; return ( 0 ) ; } void fic ( int x ) // x are number of terms to print { int a , b , sum , i ; a = b = 1 ; printf ( " 1,1, " , sum ) ; //first 2 terms for ( i = 0 ; i < x - 2 ; i + + ) { sum = a + b ; printf ( " %d , " , sum ) ; a = b ; b = sum ; } } It may be noted that using a non recu...

Objective : You are given a  number and you have to find the reverse of the given number in C. reverse of 1234 will be 4321. Programming logic : The logic lies in constructing the reverse numbers from the digits of the given number. So we extract each digit with % modulus operator and then build the number up.To build the number we simply multiply the reverse number by 10 and then add the next remainder to it. Like 1234: 1234%10=4 (remainder). rev=4. 123%10= 3. rev=4x10+3=43. 12%10=2 rev=43x10+2=432. 1%10=1 rev=432x10+1=4321. Code: # include < stdio.h > int main ( ) { int k ; printf ( " \n enter a number= " ) ; scanf ( " %d " , & k ) ; printf ( " \n Reverse of the number is= %d " , reverse ( k ) ) ; return 0 ; } int reverse ( int x ) { int ans = 0 , r ; while ( x > 0 ) { r = x % 10 ; //extract last digit ans = ans * 10 + r ; // multiply by 10 and then add the r...