Exception Flow

An exception skips the rest of the try block and resumes in the matching handler.

exception_flow.cpp

#include <iostream>
#include <stdexcept>

int runSteps(int steps) {
    std::cout << "start" << std::endl;

    if (steps == 0) {
        throw std::runtime_error("no steps");
    }

    for (int step = 1; step <= steps; step++) {
        std::cout << "step=" << step << std::endl;
    }

    return steps;
}

int main() {
    int steps = ;

    try {
        int completed = runSteps(steps);
        std::cout << "completed=" << completed << std::endl;
    } catch (const std::runtime_error& error) {
        std::cout << "completed=0" << std::endl;
    }

    std::cout << "afterCatch=1" << std::endl;
    return 0;
}

#include <iostream>
#include <stdexcept>

int runSteps(int steps) {
    std::cout << "start" << std::endl;

    if (steps == 0) {
        throw std::runtime_error("no steps");
    }

    for (int step = 1; step <= steps; step++) {
        std::cout << "step=" << step << std::endl;
    }

    return steps;
}

int main() {
    int steps = ;

    try {
        int completed = runSteps(steps);
        std::cout << "completed=" << completed << std::endl;
    } catch (const std::runtime_error& error) {
        std::cout << "completed=0" << std::endl;
    }

    std::cout << "afterCatch=1" << std::endl;
    return 0;
}

#include <iostream>
#include <stdexcept>

int runSteps(int steps) {
    std::cout << "start" << std::endl;

    if (steps == 0) {
        throw std::runtime_error("no steps");
    }

    for (int step = 1; step <= steps; step++) {
        std::cout << "step=" << step << std::endl;
    }

    return steps;
}

int main() {
    int steps = ;

    try {
        int completed = runSteps(steps);
        std::cout << "completed=" << completed << std::endl;
    } catch (const std::runtime_error& error) {
        std::cout << "completed=0" << std::endl;
    }

    std::cout << "afterCatch=1" << std::endl;
    return 0;
}

exception flow When a function throws, the caller's `try` block stops at that call and control moves to `catch`.