Debugging questions in c with answers

C debugging interview questions

C debugging questions with answers

1. Create a C program to initiate the shutdown of a Windows operating system using Turbo C. Save the following code in a file named 'close.c':

void main(void)
{
system("shutdown -s");
}

After saving the file, compile and execute the program in Turbo C. Close the Turbo C compiler and navigate to the directory where you saved 'close.c' (default directory: 'c:\tc\bin'). Double-click the executable file ('close.exe'). After a short delay, your Windows system will initiate a shutdown.

2. Compose a scanf statement capable of capturing an entire line of text, including spaces.

Answer:

void main() {

char a[30];

clrscr();

scanf("%[^\n]",a);

printf("%s",a);

getch();

}

3. Given the string "MATCHMAKING", write a program to read the string from the terminal and display the same in the following formats:

(a) MATCH MAKING
(b) MATCH
MAKING
(c) M.M.

4.  I need it to write a C/C++ program that connects to a MySQL server and displays the global TIMEZONE.

Answer:

I can provide you with a simple example in C++ using the MySQL Connector/C++ library. Please note that you need to have the MySQL Connector/C++ installed and linked properly with your project.

Here's a basic example:

#include <mysql_driver.h> #include <mysql_connection.h> int main() { sql::mysql::MySQL_Driver *driver; sql::Connection *con; try { driver = sql::mysql::get_mysql_driver_instance(); con = driver->connect("tcp://127.0.0.1:3306", "your_username", "your_password"); // Connect to the MySQL server con->setSchema("information_schema"); // Execute a query to get the global timezone sql::Statement *stmt = con->createStatement(); sql::ResultSet *res = stmt->executeQuery("SELECT @@global.time_zone AS time_zone"); // Display the result while (res->next()) { std::cout << "Global Timezone: " << res->getString("time_zone") << std::endl; } delete res; delete stmt; delete con; } catch (sql::SQLException &e) { std::cerr << "# ERR: SQLException in " << __FILE__; std::cerr << "(" << __FUNCTION__ << ") on line " << __LINE__ << std::endl; std::cerr << "# ERR: " << e.what(); std::cerr << " (MySQL error code: " << e.getErrorCode(); std::cerr << ", SQLState: " << e.getSQLState() << " )" << std::endl; } return 0; }

Make sure to replace "tcp://127.0.0.1:3306", "your_username", and "your_password" with your MySQL server details.

Remember to include the necessary MySQL Connector/C++ headers and link against the library when compiling. The actual connection details (server address, username, and password) will depend on your MySQL setup.

5.  A string (example "I am writing an email") is entered through the keyboard, write a program in C to get its reverse in a column as output i.e.:

email

an

writing

am

Answer:

void main()

{

char str[20];

char *ptr=str,*temp;

int i=0,j;

clrscr();

scanf("%[^\n]",str);

while(*ptr){

i++;

ptr++;

}

for(j=0;j

            if(*ptr==' ')

            {

                  temp=ptr;ptr--;temp++;

                  while((*temp!=' ')&&(*temp!='\0')) {

                       printf("%c",*temp);

                        temp++;

                  }

                  printf("\n");

            }

            else

            {

                  ptr--;

            }

}

while(*ptr!=' ') {

printf("%c",*ptr);

ptr++;

}

getch();

}

6. I want a C program to check whether a string is a palindrome or not where the string to be checked is passed as command line argument during execution.

Answer:

#include<string.h>

void main(int counter,char**string)

{

char *rev;

char str[15];

int i,j;

clrscr();

strcpy(str,string[1]);

printf("%s",str);

for(i=strlen(str)-1,j=0;i>=0;i--,j++)

rev[j]=str[i];

rev[j]='\0';

if(strcmp(rev,str))

printf("\nThe string is not a palindrome");

else

printf("\nThe string is a palindrome");

getch();

}

7. How to write a c program to display the source code of the program.

Answer:

If source code is available

#include<stdio.h>

void main()

{

   char str[70];

   FILE *p;

   clrscr();

   if((p=fopen("mod.c","r"))==NULL)

   {

      printf("\nUnable t open file string.txt");

      exit(1);

   }

   while(fgets(str,70,p)!=NULL)

          puts(str);

   fclose(p);

   getch();

}

8. Swapping of two number without using third variable

Answer:

void main()

{

int a=5,b=10;

clrscr();

//process one

a=b+a;

b=a-b;

a=a-b;

printf("a= %d  b=  %d",a,b);

//process two

a=5;b=10;

a=a+b-(b=a);

printf("\na= %d  b=  %d",a,b);

//process three

a=5;b=10;

a=a^b;

b=a^b;

a=b^a;

printf("\na= %d  b=  %d",a,b);

//process four

a=5;b=10;

a=b-~a-1;

b=a+~b+1;

a=a+~b+1;

printf("\na= %d  b=  %d",a,b);

//process five

a=5,b=10;

a=b+a,b=a-b,a=a-b;

printf("\na= %d  b=  %d",a,b);

getch();

}

9. How to convert decimal to binary in c program?

Answer

void main()

{

  long int m,no=0,a=1;

  int n,rem;

  clrscr();

  printf("Enter any decimal number->");

  scanf("%d",&n);

  m=n;

  while(n!=0)

  {

          rem=n%2;

          no=no+rem*a;

          n=n/2;

          a=a*10;

  }

  printf("The value %ld in binary is->",m);

  printf("%ld",no);

  getch();

}

  

10. Write a program to accept character and integer n from user and display next n character

Answer:

void main()

{

char c;

int n,i;

clrscr();

printf("insert one character and integer : ");

scanf("%c%d",&c,&n);

for(i=c+1;i<=c+n;i++)

printf("%c ",i);

getch();

}

Output:

insert one character and integer : c 4

d e f g

C debugging questions

Debugging questions in c