Programming Questions

Q:

Point out the error, if any, in the following program.

#include "stdarg.h"

main()

{

     display ( 4, 12.5, 13.5, 14.5, 44.3);

}

display(int num, ...)

{

       float c; int j;

        va_list ptr;

        va_start (ptr, num);

        for ( j = 1; j <= num; j++)

        {

            c = va_arg ( ptr, float );

            printf ("\n%f", c);

         }

}

Answer

While extracting a float argument using va_arg we should have useed 


c = va_arg (ptr, double)

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Subject: Programming

1 5479
Q:

Two main measures for the efficiency of an algorithm are

A) Time and Space B) Complexity and Memory
C) Data and Space D) Memory and Processor
 
Answer & Explanation Answer: A) Time and Space

Explanation:

Two main measures for the efficiency of an algorithm are Time and Space.

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26 5191
Q:

Write a quick script for launching a new activity within your application.

Answer

An explicit intent explicitly defines the activity the developer wishes to start. 


Script code :


Intent myIntent = new Intent(this, MyNewActivity.class);


startActivity(myIntent);

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Subject: Programming

16 5163
Q:

SNOBOL is mainly used for

A) Text Operation B) String operations
C) List operations D) Numerical operations
 
Answer & Explanation Answer: B) String operations

Explanation:

SNOBOL is a high-level computer programming language used especially in manipulating textual data. It is mainly used for string operations and was developed between 1962 and 1967.

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52 4980
Q:

Rewrite the following set of statements using conditional operators.

int a =1, b ;

if ( a > 10 )

b = 20; 

Answer

int a = 1, b , dummy;


a > 10 ? b = 20 : dummy =1;


 


Note that the following would not have worked:


a > 10 ? b = 20 : ;;


 

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Subject: Programming

3 4976
Q:

What's the difference between the functions rand(), random(), srand() and randomize()?

Answer

rand()  returns a random number


random()  returns a random number in a specified range


srand()  initialise a random number generator with a given seed value


randomize()   initializes a random number generator with a random value based o time.

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Subject: Programming

2 4862
Q:

Can I increase the size of a dynamically allocated array? < Yes / No> if yes, how?

Answer

Yes, using the realloc() function as shown below:


main()


{


        int *p;


        p = ( int *) malloc (20) ;


        t = p;


        t = (int *) realloc ( p, 40);


        if ( t == NULL )


        Printf (" Cannot reallocate, leaves previous allocated region unchanged ");


       else


       {


              if ( p ==t )


              ;  / * the array expanded at the same region */


             else


            { 


                 free ( p ); / * deallocate the original array */


                 p = t;  /* set p to newly allocated region */


             }


      }


}  

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Subject: Programming

1 4769
Q:

Undefined reference to 'pthread_create'

How to Fix this error?

Answer

This is a common error while compiling C program in Linux. This error occurs when you are using pthread_create function to create threads in your programs.


To fix this problem ensure following points:
Include header file pthread.h in your program.
Add –lpthread linker flag with compilation command.
1- Include Header file
#include <stdio.h>
#include <pthread.h>
...
...
2- Compile command
gcc main.c -o main -lpthread

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24 4716