C# Questions & Answers on Arithmetic Operators for Freshers

1. Predict the output for the following set of code.

1.  static void Main(string[] args)

2.  {

3.      float a = 16.4f;

4.      int b = 12;

5.      float c;

6.      c =  a * ( b + a) / (a - b) ;

7.      Console.WriteLine("result is :" +c);

8.      Console.ReadLine();

9.  }

a) 106
b) 104.789
c) 105.8546
d) 103.45

Answer: c

Explanation: The first expression evaluated is ‘b+a’ as both are combined. Next the expression is multiplied by operand ‘a’ i.e a (b+a) the whole result of numerator is combined and divided by denominator expression (a – b).
Output: result is : 105.8546.

2. Predict the solution for the following set of code.

1.   static void Main(string[] args)

2.   {

3.       int a, b, c, x;

4.       a = 90;

5.       b = 15;

6.       c = 3;

7.       x = a - b / 3 + c * 2 - 1;

8.       Console.WriteLine(x);

9.       Console.ReadLine();

10.   }

a) 92
b) 89
c) 90
d) 88

Answer: c

Explanation: The basic evaluation process includes two left to right passes through the expression.During first pass,the high priority operators are applied and during second pass,the low priority operators are applied as they are encountered.
First pass :
step 1 : x = 90 – 15 / 3 + 3 * 2 – 1 (15 / 3 evaluated)
step 2 : x = 90 – 5 + 3 * 2 – 1
step 3 : x = 90 – 5 + 3 * 2 -1 (3 * 2 is evaluated)
step 4 : x = 90 – 5 + 6 – 1
Second pass :
step 5 : x = 85 + 6 – 1 (90 – 5 is evaluated)
step 6 : x = 91 – 1( 85 + 6 is evaluated )
step 7 : x = 90(91 – 1 is evaluated)
Output : 90.

3. Predict the solution for the following set of code .

1.   static void Main(string[] args)

2.   {

3.       int a, b, c, x;

4.       a = 80;

5.       b = 15;

6.       c = 2;

7.       x = a - b / (3 * c) * ( a + c);

8.       Console.WriteLine(x);

9.       Console.ReadLine();

10.   }

a) 78
b) -84
c) 80
d) 98

Answer: b

Explanation: Whenever the parentheses are used,the expressions within parantheses assumes higher priority.If Two or more sets of parantheses appear one after another as shown above,the expression contained on the left side is evaluated first and right hand side last .
First pass:
Step 1: 80 – 15/(3*2)*(80 + 2)
Step 2: 80 – 15/6*82 ( (3 * 2) evaluated first and ( 80 + 2) evaluated later )
Second pass:
Step 3: 80 – 2*82
Step 4: 80 – 164.
Third pass:
Step 5 : -84. (80 – 164 is evaluated)
Output : -84 .

4. Correct order of priorities are :
a) ‘/’ > ‘%’ > ‘*’ > ‘+’
b) ‘/’ > ‘*’ > ‘%’ > ‘+’
c) ‘*’ > ‘/’ > ‘%’ > ‘+’
d) ‘%’ > ‘*’ > ‘/’ > ‘+’

Answer: c

Explanation: By definition.

5. Predict the output for the given snippet of code :

1.     int i, j = 1, k;

2.     for (i = 0; i < 3; i++)

3.     {

4.         k = j++ - ++j;

5.         Console.Write(k + " ");

6.     }

a) -4 -3 -2
b) -6 -4 -1
c) -2 -2 -2
d) -4 -4 -4

Answer: c

Explanation: Here i = 0 , j = 1.
k = 1 – 3 ( j++ = 2 and ++j = 3)
k = -2.
i = 1 , j = 3.
k = 3 – 5 ( j++ = 4 and ++j = 5)
k = -2.
i = 2 , j = 5.
k = 5 – 7 (j++ = 6 and ++j = 7)
k = -2.
Output : -2 ,-2 ,-2.

6. Predict the output for the given set of code correctly.

1.   static void Main(string[] args)

2.   {

3.       int b= 11;

4.       int c = 7;

5.       int r = 5;

6.       int e = 2;

7.       int l;

8.       int v = 109;

9.       int k;

10.       int z,t,p;

11.       z = b * c;

12.       t = b * b;

13.       p = b * r * 2;

14.       l = (b * c) + (r * e) + 10;

15.       k = v - 8;

16.       Console.WriteLine(Convert.ToString(Convert.ToChar(z)) + " " + Convert.ToString(Convert.ToChar(t)) + Convert.ToString(Convert.ToChar(p)) +   Convert.ToString(Convert.ToChar(l)) + Convert.ToString(Convert.ToChar(v)) + Convert.ToString(Convert.ToChar(k)));                

17.       Console.ReadLine();

18.   }

a) My Name
b) My nAme
c) My name
d) Myname

Answer: c

Explanation: Solving the expression l = (b * c) + (r * e) + 10 .While from left to right the parentheses are given preference first.
Step 1 : b * c is evaluated first inside first parentheses.
Step 2 : r * e is evaluated second on right side of first addition symbol .
Step 3 : After evaluating both parentheses 10 is added to value of both.
Output : My name.

7. Predict the output for the following set of code :

1.  static void Main(string[] args)

2.  {

3.      int n = 5;

4.      int x = 4;

5.      int z, c, k;

6.      for (c = 1; c <= n; c++)

7.      {

8.          for (k = 1; k <= c; k++)

9.      {

10.          z = 3 * x * x + 2 * x + 4 / x + 8;

11.          Console.Write(Convert.ToString(Convert.ToChar(z)));

12.      }

13.          Console.WriteLine("\n");

14.      }

15.      Console.ReadLine();

16.  }

a) A
AA
AAA
AAAA
b) A
AB
ABC
ABCD
c) A
AA
AAA
AAAA
AAAAA
d) A
BC
DEF
DEFG

Answer: c

Explanation: Solving the expression for value of ‘z’as 65.With,each passage of loop value number of ‘z’ increases for each row
as Row 1: A
Row 2: AA
–
–
Row 5: AAAAA
Output : A
AA
AAA
AAAA
AAAAA

8. Predict the output for the following set of code :

1.  static void Main(string[] args)

2.  {

3.      int n = 5;

4.      int x = 4;

5.      int z, c, k;

6.      z = 3 * x * x + 2 * x + 4 / x + 8;

7.      for (c = 1; c <= n; c++)

8.      {

9.          for (k = 1; k <= c; k++)

10.          {

11.              Console.Write(Convert.ToString(Convert.ToChar(z)));

12.              z++;

13.          }

14.          Console.WriteLine("\n");

15.      }

16.      Console.ReadLine();

17.  }

a) A
AA
AAA
AAAA
AAAAA
b) A
AB
ABC
ABCD
ABCDE
c) A
BC
DEF
GHIJ
KLMNO
d) A
AB
BC
BCD
BCDE

Answer: c

Explanation: Solving expression ‘z’ value is 65.Before going inside first loop
Step 1: c = 1,n = 5
k = 1,k <= 1. (as c = 1)
z = 65 converted to ‘A’ as ascii value of ‘A’ is 65.
z++ increment for next loop condition by ‘1’as 66.
Row 1: A
Step 2: c = 2, n = 5
k = 2,k <= 2. (as c = 2)
z = 66 from step 1 converted value of 66 is ‘B’.Since,k < =2
loop will again loop to second value after 66 which is 67 as z is
incremented from 66 to +1 as ’67’.so,converting ascii value of 67 to character as ‘C’.
Row 2: B C
Similarly,
Step 3:
Row 3: D E F
Step 4:
Row 4: G H I J
Step 5:
Row 5: K L M N O.
Output : A
BC
DEF
GHIJ
KLMNO

9. Choose exact solution for the following code snippet :

1.   static void Main(string[] args)

2.   {

3.       int a , b;

4.       int c = 10;

5.       int d = 12;

6.       int e = 5;

7.       int f = 6;

8.       a = c * (d + e) / f + d;

9.       Console.WriteLine(a);

10.       b = c * ( d + e / f + d);

11.       Console.WriteLine(b);

12.       if (a < b)

13.       {

14.           Console.WriteLine(" parantheses changes values");

15.       }

16.       else if (a > b)

17.       {

18.           Counterintelligence("they have same value");

19.       }

20.       Console.ReadLine();

21.   }

a) They have same value
b) Parentheses changes values
c) Since both have equal values, no conclusion
d) None of the mentioned

Answer: b

Explanation: Solving for expression ‘a’ expression inside parentheses are given preference evaluating (d+e) as 17.
a = 10 * 17/6 + 12.
a = 40.
Solving for expression ‘b’ expression inside parentheses (d + e /f + d ) are evaluated as (12 + 5/6 + 12 )
b = 10 *(12 + 5/6 + 12 ).
b = 240.
Output : 40
240
parantheses changes values.

10. The correct way of incrementing the operators are :

a) ++ a ++
b) b ++ 1
c) c += 1
d) d =+ 1

Answer: c

Explanation: This += is known as short hand operator which is same as variable = variable +1 .Similarly, a-= 1 is a = a-1, a*=1 is a = a * 1. They are used to make code short and efficient.