Loop Question 6

What will be output of following c code?

#include<stdio.h>

int main(){

    int i=1;

    for(i=0;i=-1;i=1) {

         printf("%d ",i);

         if(i!=1) break;

    }

    return 0;

}

EXPLANATION

Output: -1

Explanation:

Initial value of variable i is 1.

First iteration:

For loop initial value: i = 0

For loop condition: i = -1 . Since -1 is non- zero number. So loop condition true. Hence printf function will print value of variable i i.e. -1

Since variable i is not equal to 1. So, if condition is true. Due to break keyword program control will come out of the for loop.

Loop Question 5

What will be output of following c code?

#include<stdio.h>

int main(){

    static int i;

    for(++i;++i;++i) {

         printf("%d ",i);

         if(i==4) break;

    }

    return 0;

}

EXPLANATION

Output: 24

Explanation:

Default value of static int variable in c is zero. So, initial value of variable i = 0

First iteration:

For loop starts value: ++i i.e. i = 0 + 1 = 1

For loop condition: ++i i.e. i = 1 + 1 = 2 i.e. loop condition is true. Hence printf statement will print 2

Loop incrimination: ++I i.e. i = 2 + 1 =3

Second iteration:

For loop condition: ++i i.e. i = 3 + 1 = 4 i.e. loop condition is true. Hence printf statement will print 4.

Since is equal to for so if condition is also true. But due to break keyword program control will come out of the for loop.

Loop Question 4

What will be output of following c code?

#include<stdio.h>

int main(){

    int i,j;

    i=j=2,3;

    while(--i&&j++)

         printf("%d %d",i,j);

    return 0;

}

EXPLANATION

Output: 13

Explanation:

Initial value of variable

i = 2

j = 2

Consider the while condition : --i && j++

In first iteration:

--i && j++

= 1 && 2 //In c any non-zero number represents true.

= 1 (True)

So while loop condition is true. Hence printf function will print value of i = 1 and j = 3 (Due to post increment operator)

In second iteration:

--i && j++

= 0 && 3  //In c zero represents false

= 0  //False

So while loop condition is false. Hence program control will come out of the for loop.

Loop Question 3

What will be output of following c code?

#include<stdio.h>

int main(){

    int x=011,i;

    for(i=0;i<x;i+=3){

         printf("Start ");

         continue;

         printf("End");

    }

    return 0;

}

EXPLANATION

Output: Start Start Start

Explantion:

011 is octal number. Its equivalent decimal value is 9.

So, x = 9

First iteration:

i = 0

i < x i.e. 0 < 9  i.e. if loop condition is true.

Hence printf statement will print: Start

Due to continue keyword program control will come at the beginning of the for loop and value of variable i will be:

i += 3

i = i + 3 = 3

Second iteration:

i = 3

i < x i.e. 3 < 9 i.e. if loop condition is true.

Hence printf statement will print: Start

Due to continue keyword program control will come at the beginning of the for loop and value of variable i will be:

i += 3

i = i + 3 = 6

Third iteration:

i = 3

i < x i.e. 6 < 9 i.e. if loop condition is true.

Hence printf statement will print: Start

Due to continue keyword program control will come at the beginning of the for loop and value of variable i will be:

i += 3

i = i + 3 = 9

fourth iteration:

i = 6

i < x i.e. 9 < 9 i.e. if loop condition is false.

Hence program control will come out of the for loop.

Loop Question 2:

What will be output of following c code?

        

#include<stdio.h>

int main(){

    int i=2,j=2;

    while(i+1?--i:j++)

         printf("%d",i);

    return 0;

}

EXPLANATION

Output: 1

Explanation:

Consider the while loop condition: i + 1 ? -- i : ++j

In first iteration:

i + 1 = 3 (True)

So ternary operator will return -–i i.e. 1

In c 1 means true so while condition is true. Hence printf statement will print 1

In second iteration:

i+ 1 = 2 (True)

So ternary operator will return -–i i.e. 0

In c zero means false so while condition is false. Hence program control will come out of the while loop.

Loop Question 1

What will be output of following c code?

#include<stdio.h>

extern int x;

int main(){

    do{

        do{

             printf("%o",x);

         }

         while(!-2);

    }

    while(0);

    return 0;

}

int x=8;

EXPLANATION

Output: 10

Explanation:

Here variable x is extern type. So it will search the definition of variable x. which is present at the end of the code. So value of variable x =8

There are two do-while loops in the above code.  AS we know do-while executes at least one time even that condition is false.  So program control will reach  at printf statement at it will print octal number 10 which is equal to decimal number 8.

Note: %o is used to print the number in octal format.

In inner do- while loop while condition is ! -2 = 0

In C zero means false.  Hence program control will come out of the inner do-while loop.   In outer do-while loop while condition is 0. That is again false. So program control will also come out of the outer do-while loop.

QUIZ 26-30 ANSWERS

26.	_____ variables remain in memory until the program ends
	A. Area B. Global C. Local D. Reference E. Value Answer: Option B
27.	The outline or the definition of a function is called its
	A. beta test B. Forerunner C. Outline D. Prototype Answer: Option D
28.	Which of the following is false?
	A. Data stored in an array can be accessed faster than data stored in a disk file B. Data stored in an array needs to be entered only once, typically at the beginning of the program C. Arrays allow the programmer to store information in the computer's internal memory D. When using arrays, you will have fewer variable names to remember E. None of the preceding statements are false Answer: Option E

29.	A function typically contains
	A. the function header B. the function braces C. the return statement, if it's value- returning function D. a display message E. All of the above Answer: Option E

30.	A variable's _____ indicates which portions of the program can use the variable
	A. Area B. extent C. Lifetime D. reach E. scope Answer: Option E

QUIZ 21-25

21.	A group of related fields that contain all of the data about a specific person, place, or thing is called a
	A. data file B. field file C. program file D. Record Answer: Option D

22.	To send output to a file, you need to include the _____ header file in your program
	A. file.h B. fstream.h C. iomanip.h D. iostream.h E. of stream.h Answer: Option B

23.	A C++ _____ is a program that runs in a DOS window
	A. Algorithm B. cast application C. console application D. source application Answer: Option C

24.	A difference, between reference variables and pointers is that
	A. reference variables are easier to use B. pointers are easier to use C. reference variables are more flexible D. no difference exists between reference variables and pointers Answer: Option A

25.	A 'C function does not contain
	A. a function header B. argument declarations C. other 'C' functions D. function body E. None of the above Answer: Option C