It is necessary to understand some of the concepts used extensively in object oriented programming.These include

Objects
Classes
Data abstraction and encapsulation
Inheritance
Polymorphism
Dynamic Binding
Message passing

C++ is created by Bjarne Stroustrup of AT&T Bell Labs as an extension of C, C++ is an object-oriented computer language used in the development of enterprise and commercial applications. Microsoft’s Visual C++ became the premier language of choice among developers and programmers.

#include<stdio.h>
int main(){
  FILE *p,*q;
  char file1[20],file2[20];
  char ch;
  printf("\nEnter the source file name to be copied:");
  gets(file1);
  p=fopen(file1,"r");
  if(p==NULL){
      printf("cannot open %s",file1);
      exit(0);
  }
  printf("\nEnter the destination file name:");
  gets(file2);
  q=fopen(file2,"w");
  if(q==NULL){
      printf("cannot open %s",file2);
      exit(0);
  }
  while((ch=getc(p))!=EOF)
      putc(ch,q);
  printf("\nCOMPLETED");
  fclose(p);
  fclose(q);
 return 0;
}

#include<stdio.h>

int main(){

  int a[10][10],i,j,sum=0,m,n;

  printf("\nEnter the row and column of matrix: ");
  scanf("%d %d",&m,&n);

  printf("\nEnter the elements of matrix: ");
  for(i=0;i<m;i++)
      for(j=0;j<n;j++)
           scanf("%d",&a[i][j]);
  printf("\nThe matrix is\n");

  for(i=0;i<m;i++){
      printf("\n");
      for(j=0;j<m;j++){
      printf("%d\t",a[i][j]);
      }
 }
 for(i=0;i<m;i++){
     for(j=0;j<n;j++){
          if(i==j)
              sum=sum+a[i][j];
     }
 }
 printf("\n\nSum of the diagonal elements of a matrix is: %d",sum);

 return 0;
}

Sample output:

Enter the row and column of matrix: 3 3
Enter the elements of matrix:
2
3
5
6
7
9
2
6
7
The matrix is
2       3       5
6       7       9
2       6       7
Sum of the diagonal elements of a matrix is: 16

#include <stdio.h>

int main() {

  int a[5][5], b[5][5], c[5][5], i, j, k, sum = 0, m, n, o, p;

  printf( "\nEnter the row and column of first matrix" );

  scanf( "%d %d", &m, &n );

  printf( "\nEnter the row and column of second matrix" );

  scanf( "%d %d", &o, &p );

  if(n!=o) {

      printf( "Matrix mutiplication is not possible" );

      printf( "\nColumn of first matrix must be same as row of second matrix" );

  }

  else {

      printf( "\nEnter the First matrix" );

      for( i=0; i<m; i++ )

      for( j=0; j<n; j++ )

           scanf( "%d", &a[i][j] );

      printf( "\nEnter the Second matrix" );

      for( i=0; i<o; i++ )

      for( j=0; j<p; j++ )

           scanf( "%d", &b[i][j] );

      printf( "\nThe First matrix is\n" );

      for( i=0; i<m; i++ ) {

      printf("\n");

      for( j=0; j<n; j++ ) {

           printf( "%d\t", a[i][j] );

      }

      }

      printf( "\nThe Second matrix is\n" );

      for( i=0; i<o; i++ ) {

      printf("\n");

      for( j=0; j<p; j++ ) {

           printf( "%d\t", b[i][j] );

      }       

      }

      for( i=0; i<m; i++ )

      for( j=0; j<p;j++ )

           c[i][j] = 0;

      for( i=0; i<m; i++ ) { //row of first matrix

      for( j=0; j<p; j++ )  {  //column of second matrix

           sum = 0;

           for( k=0; k<n; k++ )

               sum = sum + a[i][k]*b[k][j];

           c[i][j] = sum;

      }

      }

  }

  printf( "\nThe multiplication of two matrix is\n" );

  for( i=0; i<m; i++ ) {

      printf("\n");

      for( j=0; j<p; j++ ) {

           printf( "%d\t", c[i][j] );

      }

  }

  return 0;

}

#include<stdio.h>
int main(){

    int a[10],i,n,m,c=0,l,u,mid;

    printf("Enter the size of an array: ");
    scanf("%d",&n);

    printf("Enter the elements in ascending order: ");
    for(i=0;i<n;i++){
         scanf("%d",&a[i]);
    }

    printf("Enter the number to be search: ");
    scanf("%d",&m);

    l=0,u=n-1;
    while(l<=u){
         mid=(l+u)/2;
         if(m==a[mid]){
             c=1;
             break;
         }
         else if(m<a[mid]){
             u=mid-1;
         }
         else
             l=mid+1;
    }
    if(c==0)
         printf("The number is not found.");
    else
         printf("The number is found.");

    return 0;
}

Sample output:
Enter the size of an array: 5
Enter the elements in ascending order: 4 7 8 11 21
Enter the number to be search: 11
The number is found.

#include<stdio.h>
int main(){

    int a[10],i,n,m,c=0;

    printf("Enter the size of an array: ");
    scanf("%d",&n);

    printf("Enter the elements of the array: ");
    for(i=0;i<=n-1;i++){
         scanf("%d",&a[i]);
    }

    printf("Enter the number to be search: ");
    scanf("%d",&m);
    for(i=0;i<=n-1;i++){
         if(a[i]==m){
             c=1;
             break;
         }
    }
    if(c==0)
         printf("The number is not in the list");
    else
         printf("The number is found");

    return 0;
}

Sample output:
Enter the size of an array: 5
Enter the elements of the array: 4 6 8 0 3
Enter the number to be search: 0
The number is found

#include
#define MAX 50

void mergeSort(int arr[],int low,int mid,int high);
void partition(int arr[],int low,int high);

int main(){
  
    int merge[MAX],i,n;

    printf("Enter the total number of elements: ");
    scanf("%d",&n);

    printf("Enter the elements which to be sort: ");
    for(i=0;i<n;i++){
         scanf("%d",&merge[i]);
    }

    partition(merge,0,n-1);

    printf("After merge sorting elements are: ");
    for(i=0;i<n;i++){
         printf("%d ",merge[i]);
    }

   return 0;
}

void partition(int arr[],int low,int high){

    int mid;

    if(low<high){
         mid=(low+high)/2;
         partition(arr,low,mid);
         partition(arr,mid+1,high);
         mergeSort(arr,low,mid,high);
    }
}

void mergeSort(int arr[],int low,int mid,int high){

    int i,m,k,l,temp[MAX];

    l=low;
    i=low;
    m=mid+1;

    while((l<=mid)&&(m<=high)){

         if(arr[l]<=arr[m]){
             temp[i]=arr[l];
             l++;
         }
         else{
             temp[i]=arr[m];
             m++;
         }
         i++;
    }

    if(l>mid){
         for(k=m;k<=high;k++){
             temp[i]=arr[k];
             i++;
         }
    }
    else{
         for(k=l;k<=mid;k++){
             temp[i]=arr[k];
             i++;
         }
    }
  
    for(k=low;k<=high;k++){
         arr[k]=temp[k];
    }
}


Sample output:

Enter the total number of elements: 5
Enter the elements which to be sort: 2 5 0 9 1
After merge sorting elements are: 0 1 2 5 9