CBSE Class 11 - Computer Science - Simple C++ Snippets (Part-5)

User-Defined Functions

c++ snippets

Q1: Write a function to return the largest number among three integers

Answer:

// function to return the largest number 
// among three integers
// function declaration
int largest_num(int , int, int);

#include <iostream.h>
#include <conio.h>

int main()
{
    // clear the screen
    clrscr(); 
    int x, y, z;
    cout << "enter 1st no.=";
    cin >> x;
    cout << "enter 2nd no.=";
    cin >> y;
    cout << "enter 3rd no.=";
    cin >> z;
    cout << "largest of three is=" << 
         largest_num(x, y, z);
    getch();
    return 0;
}

// function largest_num
// input three integers
// output: returns largest number.
int largest_num(int a, int b, int c)
{
  int max;
    if (a>b)
      {
       max = a;
      }
    else
       max = b;
    if (max < c )
      {
       max = c;
      }
  return max;
}

Q2: What is a function definition?

Answer: A function definition describes how the function computes the value it returns. It is a declaration about the function. It is also called a function prototype. In general, it is defined before using the function, within the source file or in header (.h/.hpp) files.

Q3(Text Book): Write a C++ program that reads a float array having 15 elements. The program uses a function reverse( ) to reverse this array. Make suitable assumptions wherever required.

Answer:

// // program to reverse an array
//

#include <iostream.h>
#include <conio.h>

// functions declaration
void reverse(float arry[], int size);
void display(float arry[], int size);

int main()
{
  // clear the screen
  clrscr();             
  float flist[15] = {12.2, 8.1, 6.75, 
        18.25, 30.18, 12.5, 56.0,
        78.12, 10.24, 13.12, 34.65, 
        16.80, 12.23,
      32.5, 11.25};
  display(flist, 15);
  cout <<"\nReversing the Array...\n";
  reverse(flist, 15);
  display(flist, 15);
  getch();
  return;
}

void display(float arry[], int size)
{
   cout << "The list is:\n\t";
   for (int i = 0; i < size; ++i)
  cout << arry[i] << ", ";
   cout << "\n";
}

void reverse(float arry[], int size)
{
  float temp;
  for (int i = 0; i <= size/2; ++i)
  {
 temp = arry[i];
 arry[i] = arry[size - i -1];
 arry[size - i - 1] = temp;
  }
}

Q4(Text Book): Write a complete C++ program that invokes a function satis( ) to find whether four integer a,b,c,d sent to satis( ) satisfy the equation a³ + b³ + c³ = d³ or not. The function satis( ) returns 0 if the above equation is satisfied with the given four numbers otherwise it returns -1.

Answer:

// function satis()
/* wap to find whether 4 integers 
   a,b,c,d sent to satis() 
   satisfy the
   eq. a^3 + b^3 + c^3 = d^3*/
//

#include <iostream.h>
#include <math.h>
#include <conio.h>

// functions declaration
int satis(int, int, int, int);

void main()
{
  clrscr();
  cout << "condition for F(2,3,4,6)=";
  if (satis(2,3,4,5) == 0 )
 cout << "true";
  else
  cout << "false";
  cout << "\n\nCondition for 
      F(6,8,10,12)=";
  if (satis(6,8,10,12) == 0 )
 cout << "true";
  else
  cout << "false";

  cout << endl;
  getch();
}

int satis(int a, int b, int c, int d)
{
   if ((pow(a, 3) + pow(b,3) + 
      pow(c,3)) == pow(d,3))
   return 0;
   return -1;
}

Q5(Text Book): Write a C++ program that uses the following functions:
(i) sqlarge( ) that is passed two int arguments by reference and then sets the larger of the two numbers to its square.
(ii) sum( ) that is passed an int argument by value and that returns the sum of the individual digits of the passed number.
(iii) main( ) that exercises the above two functions by getting two integers from the user and by printing the sum of the individual digits of the square of the larger number.

Answer:

// functions
/*wap that uses the function sqlarge() 
  that is passed two int arguments by
  reference & then sets the 
 larger of the two nos.to its square*/
//

#include <iostream.h>
#include <conio.h>

// functions declaration
void sqlarge(int &, int &);
int sum(int num);

void main()
{
  int first, second, sqnum;
  clrscr();
  cout << "Enter first number: ";
  cin >> first;
  cout << "Enter second number: ";
  cin >> second;
  sqlarge(first, second);
  if (first > second)
 sqnum = first;
  else
 sqnum = second;
  cout << "Square of large number = " 
     << sqnum;
  cout << "\nSum of digits of 
     square number = " << sum(sqnum);

  getch();

}

void sqlarge(int &a, int &b)
{
  if (a > b)
   a = a * a;
  else
   b = b * b;
}

int sum(int num)
{
  int s = 0;
  while (num > 0)
   {
  s += (num % 10);
  num = num / 10;
   }
  return s;
}

Q6: Write a c++ function swap( ) to swap to integers passed to the function.

Answer:

// // function swap() to 
   swap two numbers
//

#include <iostream.h>
#include <conio.h>

// functions declaration
void swap(int& x, int & y);

void main()
{
  clrscr();
    clrscr();
    int a,b;
    cout << "enter first no.=";
    cin >> a;
    cout <<"enter second no.=";
    cin >> b;
    cout << "1st No. (before swap)=" 
         << a;
   cout << "\n2nd No. (before swap)=" 
         << b;
   swap(a, b);
   cout << "\n1st Number (after swap)="
         << a;
   cout << "\n2nd number (after swap)="
         << b;
    getch();
    return 0;
}

// swap(), arguments passed as call 
   by references.
void swap(int& x, int & y)
{
    x = x + y;
    y = x - y;
    x = x - y;
}

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