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C MCQ Questions and Answers on Loops While For Do While 1

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C MCQ Questions and Answers

Learn C Programming MCQ Questions and Answers on Loops like While Loop, For Loop and Do While Loop. Loops execute a series of statements until a condition is met or satisfied. Easily attend exams after reading these Multiple Choice Questions.

Go through C Theory Notes on Loops before studying questions.



1) Choose a right C Statement.
A) Loops or Repetition block executes a group of statements repeatedly.
B) Loop is usually executed as long as a condition is met.
C) Loops usually take advantage of Loop Counter
D) All the above.
Answer [=]
D
2) Loops in C Language are implemented using.?
A) While Block
B) For Block
C) Do While Block
D) All the above
Answer [=]
D
3) Which loop is faster in C Language, for, while or Do While.?
A) for
B) while
C) do while
D) All work at same speed
Answer [=]
D
4) Choose correct C while loop syntax.
A) while(condition) { //statements }
B) { //statements }while(condition)
C) while(condition); { //statements }
D) while() { if(condition) { //statements } }
Answer [=]
A
5) Choose a correct C for loop syntax.
A) for(initalization; condition; incrementoperation) { //statements }
B) for(declaration; condition; incrementoperation) { //statements }
C) for(declaration; incrementoperation; condition) { //statements }
D) for(initalization; condition; incrementoperation;) { //statements }
Answer [=]
A
Explanation:

increment or decrement operation at third place.

6) Choose a correct C do while syntax.
A) dowhile(condition) { //statements }
B) do while(condition) { //statements }
C) do { //statements }while(condition)
D) do { //statements }while(condition);
Answer [=]
D
Explanation:

Semicolon after while(condition) is a must.

7) What is the output of C Program.? int main() { while(true) { printf("RABBIT"); break; } return 0; }
A) RABBIT
B) RABBIT is printed unlimited number of times.
C) No output
D) Compiler error.
Answer [=]
D
Explanation:

while(TRUE) or while(true) does not work. true is not a keyword.

8) What is the output of C Program.? int main() { int a=5; while(a==5) { printf("RABBIT"); break; } return 0; }
A) RABBIT is printed unlimited number of times
B) RABBIT
C) Compiler error
D) None of the above.
Answer [=]
B
Explanation:

If there is no BREAK statement, while loop runs continuously util the computer hangs. BREAK causes the loop to break once and the statement below the while if any will be executed.

9) What is the output of C Program.? int main() { int a=5; while(a=123) { printf("RABBIT\n"); break; } printf("GREEN"); return 0; }
A) GREEN
B) RABBIT GREEN
C) RABBIT is printed unlimited number of times.
D) Compiler error.
Answer [=]
B
Explanation:

while(a=123)  = while(123) = while(Non Zero Number). So while is executed. BREAK breaks the loop immediately. Without break statement, while loop runs infinite number of times.

10) What is the output of C Program.? int main() { int a=5; while(a >= 3); { printf("RABBIT\n"); break; } printf("GREEN"); return 0; }
A) GREEN
B) RABBIT GREEN
C) RABBIT is printed infinite times
D) None of the above
Answer [=]
D
Explanation:

Notice a semicon(;) after while condition. It makes the printf and break statement blocks isolate.

while(a >= 3)
{
    ;//infinite loop
}
{
    printf("RABBIT\n");
    break;
}
11) What is the output of C Program.? int main() { int a=25; while(a <= 27) { printf("%d ", a); a++; } return 0; }
A) 25 25 25
B) 25 26 27
C) 27 27 27
D) Compiler error
Answer [=]
B
Explanation:

a++ is equivalent to a=a+1;

a is incremented each time.

12) What is the output of C Program.? int main() { int a=32; do { printf("%d ", a); a++; }while(a <= 30); return 0; }
A) 32
B) 33
C) 30
D) No Output
Answer [=]
A
Explanation:

do { } block is executed even before checking while(condition) at least once. This prints 32. To loop for the second time, while (32 <= 30) fails. So, loop is quit.

13) What is the output of C Program.? int main() { int a=32; do { printf("%d ", a); a++; if(a > 35) break; }while(1); return 0; }
A) No Output
B) 32 33 34
C) 32 33 34 35
D) Compiler error
Answer [=]
C
Explanation:

while(1) is infinite loop. So we kept if(condition) to break the loop. a++ is equivalent to a=a+1;

14) Choose a correct C Statement.
A) a++ is (a=a+1) POST INCREMENT Operator
B) a-- is (a=a-1) POST DECREMENT Opeartor --a is (a=a-1) PRE DECREMENT Opeator
C) ++a is (a=a+1) PRE INCRMENT Operator
D) All the above.
Answer [=]
D
15) Choose correct Syntax for C Arithmetic Compound Assignment Operators.
A) a+=b is (a= a+ b) a-=b is (a= a-b)
B) a*=b is (a=a*b) a/=b is (a = a/b)
C) a%=b is (a=a%b)
D) All the above.
Answer [=]
D
16) What is the output of C Program.? int main() { int k, j; for(k=1, j=10; k <= 5; k++) { printf("%d ", (k+j)); } return 0; }
A) compiler error
B) 10 10 10 10 10
C) 10 11 12 13 14 15
D) None of the above
Answer [=]
C
Explanation:

You can initialize any number of variables inside for loop.

17) What is the output of C Program.? int main() { int k; for(k=1; k <= 5; k++); { printf("%d ", k); } return 0; }
A) 1 2 3 4 5
B) 1 2 3 4
C) 6
D) 5
Answer [=]
C
Explanation:

Semicolon at the end of for(); isolates the below print() block. After for loop is over, k value is 6.

for(k=1; k <= 5; k++)
{
    ;
}
{
    printf("%d ", k);
}
18) What is the output of C Program.? int main() { int k; for(;;) { printf("TESTING\n"); break; } return 0; }
A) No Output
B) TESTING
C) Compiler error
D) None of the above
Answer [=]
B
Explanation:

for(;;) loop need not contain any initialization, condition and incre/decrement sections. All are optional. BREAK breaks the FOR Loop.

19) What is the output of C Program.? int main() { int k; for(printf("FLOWER "); printf("YELLOW "); printf("FRUITS ")) { break; } return 0; }
A) Compiler error
B) FLOWER FRUITS
C) FLOWER YELLOW
D) FLOWER YELLOW FRUITS
Answer [=]
C
Explanation:

for(anything; anything; anything) is Ok. printf("YELLOW") prints YELLOW and returns 1 as result. So for loop runs forever. Actually break is saving us from quitting the for loop. Only after checking condition and executing the loop statements, third section is executed. break causes the loop to quit without incre/decrement section.

20) What is the way to suddenly come out of or Quit any Loop in C Language.?
A) continue; statement
B) break; statement
C) leave; statement
D) quit; statement
Answer [=]
B
Explanation:
eg.
while(condition)
{
break;
}