Control Structures — Part 1 MCQs with Explanations

In C, a do-while loop executes its body at least once, even if the condition is initially false. This is because the condition is evaluated after the body of the loop has been executed. If the condition is false after the first execution of the body, the loop terminates. Therefore, even if the condition is initially false, the loop body will execute once before the condition is evaluated. So, the correct answer is Option B: 1 time .

since this program isn't having any syntax error so program is executed. It is clearly seen that 99 is not divisible by 5. So if statement will not execute and program will terminate.

When we give scanf () a "%f" format string, that means "We want you to try and get us a floating point number. When we provide input like 'xyz', it's not going to match anything, because 'xyz' is not a valid floating-point number.

When we give scanf () a "%f" format string, that means "We want you to try and get us a floating point number. When we provide input like 'xyz', it's not going to match anything, because 'xyz' is not a valid floating-point number.

The scope of second declaration of i is limited to the block in which it is defined. Outside of the block variable is not recognized.

comma operator is executed from left to right so until j<20 for loop statement is true, so both i and j are incremented. So, i = 20 and j = 20.

for loop can be initialized outside of the loop. Since until -1 value of i remain a non-zero value and hence the condition is true up to -1. But when i is further increases its value becomes 0 and condition becomes false and loop stops there. Note :In C any non-zero value(positive or negative) evaluates to true and only zero value is evaluates to false .

Here if condition evaluates to true as a non-zero value i.e 5 is assigned to a. So the value of a = 5 and after increment value of b = 6. In printf statement due to pre-increment of a value of a printed will be 6 and due to post-increment of b value of b printed will be 6 and not 7.

As the value of variable value is zero so, it evaluates to false in the if condition.

Expression value2%5 is equal to 0 and this value assigned to value1. Therefore if condition reduces to if ( 0 ) so it fails. Therefore body of if will not be executed i.e num = 5 will not be assigned. So at printf num = 100 , value1 = 0 and value2 = 100 .

compiler error switch expression is not integral. switch statement cannot work on float value.

the if is conditional and it checks for expression whether it is zero or non-zero so it doesn't print any data it is clear and it is clearly seen that there is not a single syntax error therefore no complier error. After compling the program will be executed but there is not a single printf statement so it is executed but will not give any output.

Decrement operator in for loop statement are executed until the condition is true. So it is executed till " a " not equal to zero and printf statement inside for loop print a value of " a "

Here if statement is executed since we know that printf () function return the number of character print. Here printf ( " %d ", i ) return 2 because it print 1 and newline i.e 2. And, printf ( " %d ', j ) return 3 because it print -1 and newline i.e number of character is 3. Therefore if statement look like if( 2<3) yes its true. So if statement will execute. And answer is 1 -1 1.

Due to semicolon(;) at the end of the for loop, after 10 iterations for loop will be terminated and the result will be 10.

' If ' statement only true when value of ' s ' is less then 4

Syntax: continue ; Causes control to pass to the end of the innermost enclosing while, do, or for statement, at that point the loop continuation condition is re-evaluated. Example: for (i = 0; i < 20; i ++ ) { if (array[i] == 0) continue ; array[i] = 1/array[i]; }

Condition if(c[a]%2 == 1) forces only odd numbers to add in the sum.

Since the condition is always true it will go to infinite loop.

In for loop the three statements parts are separated by two semicolons which are missing here.

Here if Statement is true and if statement executes left to right. Since its AND operator so all the condition should be check until it finds any false statement. Initially y = 10 In 1st condition: y++>9 which is true and y become 11 in next use. In 2nd condition: y++!=10 which is also true and y become 12 in next use In 3rd condition: y++>11 which is also true and y become 13 in next use After that printf statement will execute and print y = 13

As the value of num is decremented(--num) and again incremented(++num) and hence no change in num and it remains 0 only causing infinite loop.

First of all for loop have no braces so for loop on have only next line in its body. for( ; digit <= 9; ) digit++; After completing for loop digit = 10; next statement digit *= 2; i.e digit = digit * 2 = 20 ; next statement digit--; i.e 20-- => 19 So final value of digit is 19

As the first option is matching, the cases are evaluated till the break statement is encountered or end of switch statement is encountered.

It is summation of 1+2+3+4+5 as continue statement is going to be executed for every input of -1, -2, -3, -4, -5.

break can't be used with selection control structures, but can used with repetitive( for, while ), or select control structure( switch ).

The correct answer is D: Compile time error Here's why: In C, the `break` statement is used to exit loops (like `for`, `while`, or `do-while`) or `switch` statements. It's designed to jump out of these control structures. In this code, `break` is placed directly inside an `if` block, but not within any loop or `switch`. The C compiler will detect that `break` is used in an invalid context. Therefore, the program will result in a compile-time error , indicating that the `break` statement is misplaced. The program won't even run. In summary: The `break` statement is only valid inside loops or `switch` statements.

#include <stdio.h> : This line includes the standard input/output library, which is needed for the printf function. int x; : This declares an integer variable named x . Crucially, x is declared globally but *not* initialized . This means it will have a default value. void main() : This is the main function where the program execution begins. if (x) : This is the core of the question. The if statement checks the value of x . In C, any non-zero value is treated as true , and zero is treated as false . printf("hi"); : This line will be executed if the condition x is true . else printf("how are u"); : This line will be executed if the condition x is false . Now, the key point is that since x is a global variable and is not explicitly initialized , it's automatically initialized to 0 by the C compiler. Therefore, the condition if (x) is equivalent to if (0) , which is false . So, the else block will be executed, and the program will print "how are u". Therefore, the correct answer is Option B: how are you

In this code, the switch statement is evaluating the result of the printf("Do") function call. The printf() function returns the number of characters printed. When printf("Do") is executed, it prints "Do" to the standard output and returns the number of characters printed, which is 2. So, the switch statement evaluates the value 2. Since there is a case 2 in the switch statement, it will execute the corresponding code block, which prints "Second" to the standard output. Therefore, the correct output of the code will be DoSecond . So, the correct answer is Option C: DoSecond .

while loop is the correct answer to “Which control structure is used to repeatedly execute a block of code in C”. This question is standard in competitive examination syllabi for Control Structures.

Terminate the loop and exit it is the correct answer to “In C, what is the purpose of the 'break' statement within a loop”. This question is standard in competitive examination syllabi for Control Structures.

Execute the 'else' block is the correct answer to “What is the purpose of the 'else' statement in C's 'if-else' control structure”. This question is standard in competitive examination syllabi for Control Structures.

if statement is the correct answer to “Which control structure is used to make a decision between two or more alternatives in C”. This question is standard in competitive examination syllabi for Control Structures.

TRUE is the correct answer to “What is the result of the expression 5 > 3 && 4 < 6 in C”. This question is standard in competitive examination syllabi for Control Structures.

It has no effect is the correct answer to “In C, what happens if the 'default' case is missing in a 'switch' statement”. This question is standard in competitive examination syllabi for Control Structures.

Skip the current iteration is the correct answer to “What is the purpose of the 'continue' statement in C”. This question is standard in competitive examination syllabi for Control Structures.

FALSE is the correct answer to “What is the result of the expression !(5 == 5) in C”. This question is standard in competitive examination syllabi for Control Structures.

for loop is the correct answer to “In C, which control structure is used to iterate through a collection of items, such as an array or a list”. This question is standard in competitive examination syllabi for Control Structures.

Decision making is the correct answer to “What is the purpose of the 'if' control structure in C”. This question is standard in competitive examination syllabi for Control Structures.

It generates a compilation error is the correct answer to “In C, what happens if the 'break' statement is used outside of a loop or switch statement”. This question is standard in competitive examination syllabi for Control Structures.