C / C++ / MFC

FILE * fp = fopen("foo.txt", "rb+");

Chandru080 wrote:

Now at a later point of time i need to open the same file and append. starting writing from the third row. How can i do that?

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

   int i;

  // srand is used to generate different number on each startup of generation.
   srand( (unsigned)time( NULL ) );

   /* Display 10 numbers. */
   for( i = 0;   i < 10;i++ )
   // For the range of 0 to 20 you can use
      printf( "  %6d\n", rand()%20 );

	return nRetCode;
}

std::set < int > foo;
for (int i=0;i<20;i++)
{
    int z = rand() % 100;
    if (foo.find(z) == foo.end())
    {
        foo.insert(z);
        TRACE("+%d\n", z);
    }
    else
    {
        TRACE("skip %d\n", z);
    }
}

Le@rner wrote:

error C2039: 'set' : is not a member of 'std'

const int N = 20; // bag size
int num[N]; //the numbers
int i;
for (i=0; i<N; i++)// initialize the sequence
{
  num[i] = i+1; 
}

for (int i=0; i<N-1; i++) // scramble the sequence
{
  int r = rand() % (N-i); // choose a number in the 'unextracted' sequence
  // put num[r] at the end of the sequence, since it was extracted
  // this is achieved by swapping r and N-1-i items.
  int temp = num[N-1-i];
  num[N-1-i] = num[r];
  num[r]= temp;
}
//print out the scrambled sequence
for (i=0; i<N; i++)
{
  cout << num[i] << endl;
}

Le@rner wrote:

i want to generate random number but not repeated.

void main( void )
{
    int array[10] = {0};
    int n = 10;
  
    for (int i = 0; i < n; i++)
        array[i] = i;
  
    random_shuffle(array, array + 10);
}