Operators and Expressions : MCQs & PYQs with Explanation

Option D

Type Conversion is needed to convert a value from one data type to another so that it can be properly stored or used in a variable of a different type.

Option D

The operators + (addition), * (multiplication), and / (division) can work with both integer and floating-point operands. There is no restriction that these operators must take only integer operands.

Option C

The conditional operator is also called the ternary operator because it works with three operands.
Syntax:
(condition) ? True Part : False Part;

#include <stdio.h>
int main()
{
    int a,p,q,min;
    printf("Enter A Number : ");
    scanf("%d",&a);
    a%2==0?printf("%d is Even",a):printf("%d is Odd",a);
    printf("
Enter Two Number : ");
    scanf("%d%d",&p,&q);
    min=p<q?p:q;
    printf("Minimum : %d",min);
    return 0;
}
OUTPUT
Enter A Number : 89
89 is Odd
Enter Two Number : 63 58
Minimum : 58

Option A

The operators && (AND) and || (OR) are called logical operators. They are used to combine multiple conditions in decision-making statements like if, while, or for.

• && (logical AND) : True only if both conditions are true.
• || (logical OR) : True if at least one condition is true.
• ! (logical NOT) : Reverse the logical value of a condition.

#include <stdio.h>
int main()
{
    int a, b;
    printf("Enter two Numbers: ");
    scanf("%d%d",&a,&b);
    if (a>0 && b>0)
    {
        printf("Both Numbers are Positive.
");
    }
    if (a<0 || b<0)
    {
        printf("At least One Number is Negative.
");
    } 
    if (!(a == b)) 
    {
        printf("The Numbers are Not Equal.");
    }
    return 0;
}
OUTPUT
Enter two Numbers: -87 56
At least One Number is Negative.
The Numbers are Not Equal.

Option A

The higher order precedence of given operators is:

• Unary operator.
• Arithmetic operator.
• Conditional operator.
• Assignment operator.

Option B

After b=10; and c=15;, the statement a = ++b + c++; evaluates as follows in C: 

• The ++b is pre-increment, so b becomes 11 and contributes 11 to the sum.
• The c++ is post-increment, so it contributes its original value 15 to the sum while c then becomes 16 afterward. 

Thus, a=11+15 = 26, with final values a=26, b=11, c=16.

Option B

The modulus operator (%) is used to find the remainder after division of two integers. The sign of the result of % depends on the sign of the left operand (dividend). So, so -17%5 results in -2.
Note:
For solving % operator, there is no direct approach so it can be solved by using the equation, a%b=a-(a/b)*b and sign of remainder is determined by sign of first operand left to % symbol (dividend).
Now, the given expression is −17%5. Here a is -17 and b is 5.
a%b=a-(a/b)*b
-17%5 = -17-(-17/5)*5
-17%5 = -17-(-3*5)
-17%5 = -17+15
-17%5 = -2

Option B

The comma operator evaluates expressions from left to right, and the value of the entire expression is the value of the last expression.

Option D

The assignment operator is represented by the symbol =. It is used to assign a value to a variable.
The associativity of the assignment operator is Right to Left. This means that when multiple assignment operators appear in the same expression, evaluation starts from the right side.
E.g.:
int a,b,c;
a=b=c=5;
This statement is evaluated as a=(b=(c=5));

Option B

In the given statement printf("%d",(17*2)%(int)5.5); first, 17*2 gives 34. Then type casting is applied, where (int)5.5 converts the floating-point value 5.5 into the integer value 5 by removing the decimal part. 
After this, the expression becomes 34%5. The modulus operator returns the remainder after division, and when 34 is divided by 5, the remainder is 4. Therefore, the value printed by printf() is 4.

Option B

In C, operators follow precedence and associativity rules. Also, assignment operations are evaluated from Right to Left.
Initially, the value of x is 2. In the first statement x*=3+2, the addition is performed first, so 3+2 = 5, and then x is multiplied by 5, making x = 2*5 = 10.
In the next statement x*=y=z=4, assignment operators are evaluated from right to left. So first z is assigned 4, then y is assigned 4. After that, the expression becomes x *= 4, so x = 10*4 = 40.
Finally, the printf statement prints the value of x, which is 40.

Option D

Option C

Option C

The float variables a and b are first initialized with the values 2 and 3, respectively. The expression b *= +28.5 is evaluated first, which is equivalent to b = 3*28.5, resulting in b = 85.5. Next, the expression a *= b is evaluated, which is equivalent to a = 2*85.5, resulting in a = 171. 
Finally, when printf("%f",a); is executed, the float value of a is printed in standard floating-point format as 171.000000.

Option A

In the given expression n = m++ + ++m - --m;, starting with m = 3, the value used by m++ is 3 and then m becomes 4, next ++m makes m equal to 5 and uses 5, and then --m reduces m to 4 and uses 4. After all operations, the final value of m becomes 4.
Note:
It is important to note that modifying the same variable multiple times within a single expression leads to undefined behavior in standard C, but in competitive exams, it is usually evaluated step by step as shown above.