Ternary operator in C - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of nested ternary operator

What is the output of this C code snippet?

C

int x = 5, y = 10;
int result = x > y ? x : y > 7 ? y : x;
printf("%d", result);

A 5

B 10

C 7

D Compilation error

💡 Hint

Remember how nested ternary operators are evaluated from left to right.

The expression evaluates as x > y ? x : (y > 7 ? y : x). Since x=5 is not greater than y=10, it checks y > 7 which is true, so result is y=10.

❓ Predict Output

intermediate

Ternary operator with side effects

What will be printed by this code?

C

int a = 3, b = 4;
int c = (a > b) ? (a += 2) : (b += 3);
printf("%d %d %d", a, b, c);

A 3 4 4

B 5 4 5

C Compilation error

D 3 7 7

💡 Hint

Check which condition is true and how the variables change.

Since a=3 is not greater than b=4, the else part runs: b += 3 makes b=7, c=7, a remains 3.

❓ Predict Output

advanced

Ternary operator with pointer dereference

What is the output of this code?

C

int x = 10, y = 20;
int *p = (x > y) ? &x : &y;
printf("%d", *p);

A 10

B 0

C 20

D Segmentation fault

💡 Hint

Check which pointer is assigned based on the condition.

Since x=10 is not greater than y=20, pointer p points to y, so *p is 20.

❓ Predict Output

advanced

Ternary operator with different types

What will this code print?

C

int a = 5;
float b = 3.5;
float c = (a > 3) ? a : b;
printf("%.1f", c);

A 5.0

B Compilation error

C 5

D 3.5

💡 Hint

The ternary operator promotes types to a common type.

Since a=5 > 3, c is assigned a converted to float 5.0, so it prints 5.0.

🧠 Conceptual

expert

Ternary operator associativity

Consider the expression: int x = 1 ? 0 ? 2 : 3 : 4; What is the value of x after this executes?

A 3

B 2

C 4

D Compilation error

💡 Hint

Ternary operators associate right to left in C.

Expression groups as: 1 ? (0 ? 2 : 3) : 4. Since 1 is true, evaluate (0 ? 2 : 3) which is 3, so x=3.