Assignment and compound assignment in C Sharp (C#) - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of compound assignment with strings

What is the output of this C# code snippet?

C Sharp (C#)

string s = "Hi";
s += " there";
Console.WriteLine(s);

A Hi there

B Hi

C there

D Hi+ there

💡 Hint

The += operator adds the right string to the left string.

The += operator appends the string on the right to the string on the left, so s becomes "Hi there".

❓ Predict Output

intermediate

Value after compound assignment with integers

What is the value of x after running this code?

C Sharp (C#)

int x = 5;
x *= 3 + 2;
Console.WriteLine(x);

A 10

B 15

C 25

D 30

💡 Hint

Remember operator precedence: multiplication and addition.

The expression x *= 3 + 2 is evaluated as x *= (3 + 2), so x = 5 * 5 = 25.

❓ Predict Output

advanced

Output of compound assignment with mixed types

What is the output of this code?

C Sharp (C#)

double d = 4.5;
int i = 2;
d /= i;
Console.WriteLine(d);

A 2

B 2.25

C 2.5

D Syntax error

💡 Hint

Division between double and int results in double.

d /= i divides d by i, so 4.5 / 2 = 2.25.

❓ Predict Output

advanced

Effect of compound assignment on boolean variables

What error or output does this code produce?

C Sharp (C#)

bool flag = true;
flag += false;
Console.WriteLine(flag);

A Compilation error

B True

C False

D Runtime error

💡 Hint

Can you add booleans with += in C#?

The += operator is not defined for bool types, so this causes a compilation error.

🧠 Conceptual

expert

Understanding compound assignment with nullable types

Given the code below, what is the value of n after execution?

C Sharp (C#)

int? n = null;
n ??= 10;
n += 5;
Console.WriteLine(n);

A Compilation error

B 5

C null

D 15

💡 Hint

The ??= operator assigns only if the variable is null.

n starts as null, so n ??= 10 sets n to 10. Then n += 5 adds 5, so n becomes 15.