grade_report.cpp in C++

Averages and bests per student, printed as an aligned table with std::format.

#include <algorithm>
#include <format>
#include <iostream>
#include <numeric>
#include <string>
#include <vector>

// grade_report: per-student averages in aligned columns

struct Student {
    std::string name;
    std::vector<int> scores;
};

int main() {
    const std::vector<Student> roster = {
        {"Ada", {92, 88, 95}},
        {"Grace", {85, 91, 89}},
        {"Alan", {78, 82, 80}},
        {"Edsger", {90, 94, 97}},
    };

    std::cout << std::format("{:<8} {:>7} {:>5}\n",
                             "name", "average", "best");
    std::cout << std::string(22, '-') << "\n";

    double class_total = 0.0;
    for (const auto &[name, scores] : roster) {
        double avg = std::accumulate(scores.begin(), scores.end(), 0.0)
                     / scores.size();
        int best = *std::ranges::max_element(scores);
        class_total += avg;
        std::cout << std::format("{:<8} {:>7.1f} {:>5}\n",
                                 name, avg, best);
    }

    std::cout << std::string(22, '-') << "\n";
    std::cout << std::format("class average: {:.1f}\n",
                             class_total / roster.size());
}

How it works

1. Each Student carries a name and a vector of scores; the roster is brace-initialized.
2. Structured bindings unpack each student; std::accumulate over 0.0 averages the scores.
3. {:<8} {:>7.1f} {:>5} keeps every row in the same columns as the header.
4. The running class_total divides out to a class average under the rule line.

Keywords and builtins used here

• Student
• auto
• const
• double
• for
• int
• main
• struct

The run, in numbers

Lines

40

Characters to type

925

Tokens

306

Three-star pace

80 tpm

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Type this snippet

Step 2 of 3 in Encore, step 26 of 27 in Language basics.

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