Exercises · T01 variables calculations

Covers: declaration, initialization, types, const, arithmetic, operator precedence, type conversion, static_cast, formatted output. Lectures L03–L06 (and L01–L02 warm-ups). Outcomes PF-1.x, PF-2.x, PF-3.x.

13 exercises · difficulty ladder runs 🟢 → 🔴.

PF-E-001 · Hello, You

Difficulty: Beginner · Lecture: L01 · Outcomes: PF-1.1 Prerequisites: none Problem: Print two lines: Hello, world! then Ready to learn C++. Compile and run. Input: none · Output: exactly the two lines. Sample: — → Hello, world! / Ready to learn C++. Hints: one statement per line of output; end each with \n.

PF-E-002 · Blank-Frame Printer

Difficulty: Beginner · Lecture: L02 · Outcomes: PF-1.1 Prerequisites: E-001 Problem: Print a 5-line frame of asterisks (width 12) with two blank interior lines. Input: none · Output: the frame. Sample: — → ********* / ` / / / ******` Hints:* count the lines before typing; every line is a separate statement.

PF-E-003 · Age in Days

Difficulty: Beginner · Lecture: L03 · Outcomes: PF-2.1 Prerequisites: E-001 Problem: Read an age in whole years; print the (approximate) age in days, assuming 365 days per year. Input: one integer (years) · Output: one integer (days). Sample: 20 → 7300 Hints: one multiplication; store the result in a variable before printing.

PF-E-004 · Temperature Converter (C→F)

Difficulty: Beginner · Lecture: L03 · Outcomes: PF-2.1, PF-3.2 Prerequisites: E-003 Problem: Read a Celsius temperature (may have decimals); print Fahrenheit with one decimal place. Input: one double · Output: one double, one decimal place. Sample: 36.6 → 97.9 Hints: F = C × 9/5 + 32; use 9.0/5.0 — why does 9/5 fail?

PF-E-005 · Circle Report

Difficulty: Beginner · Lecture: L03 · Outcomes: PF-2.1, PF-2.3 Prerequisites: E-004 Problem: Read a radius; print diameter, circumference, and area, each labeled, each with 2 decimals. Declare π as a const double. Input: one double (radius) · Output: three labeled values. Sample: 2.5 → diameter: 5.00 / circumference: 15.71 / area: 19.63 Hints: const double PI{3.141592653589793};

PF-E-006 · Receipt Line

Difficulty: Beginner · Lecture: L04 · Outcomes: PF-2.2, PF-2.3 Prerequisites: E-005 Problem: Read an item name (one word), unit price, and quantity. Print a fixed-width receipt line: name left-aligned width 12, quantity width 4, total price (price × qty) width 10 with 2 decimals. Input: string, double, int · Output: one formatted line. Sample: Mouse 499.50 3 → Mouse 3 1498.50 Hints: <iomanip>: std::setw, std::left, std::fixed, std::setprecision.

PF-E-007 · Digit Splitter

Difficulty: Foundational · Lecture: L05 · Outcomes: PF-3.1, PF-3.3 Prerequisites: E-003 Problem: Read a two-digit integer; print its tens digit and units digit, separated by a space. Then print their sum and product. Input: one integer 10–99 · Output: digits, then sum, then product. Sample: 47 → 4 7 / sum: 11 / product: 28 Hints: % 10 and / 10; no strings allowed.

PF-E-008 · Seconds Decomposer

Difficulty: Foundational · Lecture: L05 · Outcomes: PF-3.1 Prerequisites: E-007 Problem: Read a total number of seconds; print it as hours, minutes, seconds. Input: one non-negative integer · Output: H:MM:SS with zero-padded minutes/seconds. Sample: 7385 → 2:03:05 Hints: std::setw(2) << std::setfill('0') for padding; decompose from the largest unit.

PF-E-009 · Coin Change (Static)

Difficulty: Foundational · Lecture: L05 · Outcomes: PF-3.1, PF-3.3 Prerequisites: E-008 Problem: Read an amount in cents (0–999); print the fewest coins (25, 10, 5, 1) that make it. Input: one integer (cents) · Output: four labeled counts. Sample: 187 → 25c: 7 / 10c: 1 / 5c: 0 / 1c: 2 Hints: greedy: take as many of the largest coin as possible, then move down.

PF-E-010 · Swap Visualization

Difficulty: Foundational · Lecture: L05 · Outcomes: PF-3.1, PF-3.2 Prerequisites: E-003 Problem: Read two integers into a and b. Print them, swap their values using a temporary variable, and print them again. Then predict (in a comment) what happens without the temporary — and demonstrate it in a second, labeled block. Input: two integers · Output: values before and after each swap. Sample: 3 8 → before: 3 8 / after good swap: 8 3 / after bad swap: 0 8 Hints: the "bad swap" is a = b; b = a; — trace why the first value is lost.

PF-E-011 · Expression Forensics

Difficulty: Intermediate · Lecture: L05 · Outcomes: PF-3.1, PF-3.4 Prerequisites: E-007, E-009 Problem: Given the declarations int a{7}; double b{2.0}; int c{3};, write a program that prints the value and type-behavior of five expressions: a / c, a / b, a % c, a + b c, (a + b) c. First write your predicted answers in comments, then print actual values and compare. Input: none · Output: five labeled lines with actual values. Sample: — → a/c: 2 / a/b: 3.5 / … Hints: decide integer vs floating-point per expression before compiling.

PF-E-012 · Salary Calculator

Difficulty: Intermediate · Lecture: L06 · Outcomes: PF-2.1, PF-3.2 Prerequisites: E-006, E-011 Problem: Read hourly wage, regular hours, and overtime hours. Overtime pays 1.5×. Compute gross pay, deduct 11% income tax and 180 fixed transport levy, print a payslip (gross, each deduction, net) with aligned columns and 2 decimals. Input: double, double, double · Output: four labeled money values. Sample: 50 40 5 → gross: 2375.00 / tax: 261.25 / levy: 180.00 / net: 1933.75 Hints: compute overtime at the multiplied rate; one variable per payslip line keeps printing trivial.

PF-E-013 · Deterministic Chaos (Integer Overflow)

Difficulty: Advanced Introductory · Lecture: L06 · Outcomes: PF-3.2, PF-3.4 Prerequisites: E-011 Problem: Starting from int n{1};, repeatedly print n, then compute n *= 10; n += 7; ten times, printing each step. After each step also print the value computed as long long from the same formula. Write a short comment explaining exactly where (and why) the int version stops matching the long long version. Input: none · Output: 10 lines: step, int value, long long value. Sample: first lines → 1: 17 17 / 2: 177 177 / … then they diverge. Hints: int is 32-bit on our toolchain — typical, not guaranteed (say so in the comment).