Namespaces and Organization

Namespace Basics

A namespace groups related names so they do not crowd the global scope.

namespace A namespace wraps functions, types, or variables inside a named group.

Namespace Basics

value
namespace_basics.cpp
Replay: real traced execution (multi-file project)
#include <iostream>

namespace math_tools {
int doubleValue(int number) {
    return number * 2;
}
}

int main() {
    int value = 4;

    int result = math_tools::doubleValue(value);

    std::cout << "value=" << value << std::endl;
    std::cout << "result=" << result << std::endl;
    return 0;
}

#include <iostream>

namespace math_tools {
int doubleValue(int number) {
    return number * 2;
}
}

int main() {
    int value = 7;

    int result = math_tools::doubleValue(value);

    std::cout << "value=" << value << std::endl;
    std::cout << "result=" << result << std::endl;
    return 0;
}

#include <iostream>

namespace math_tools {
int doubleValue(int number) {
    return number * 2;
}
}

int main() {
    int value = 10;

    int result = math_tools::doubleValue(value);

    std::cout << "value=" << value << std::endl;
    std::cout << "result=" << result << std::endl;
    return 0;
}

  1. value ← 4

    9int main() {10    int value→ 4 = 4; //@value=7, 101112    int result = math_tools::doubleValue(value4);

  2. int doubleValue(int number)

    3namespace math_tools {4int doubleValue(int number4) {5    return number4 * 2;6}

  3. result ← 8

    12    int result→ 8 = math_tools::doubleValue(value4);1314    std::cout << "value=" << value4 << std::endl;15    std::cout << "result=" << result8 << std::endl;16    return 0;17}
    outputvalue=4
result=8

  1. value ← 7

    9int main() {10    int value→ 7 = 7;1112    int result = math_tools::doubleValue(value7);

  2. int doubleValue(int number)

    3namespace math_tools {4int doubleValue(int number7) {5    return number7 * 2;6}

  3. result ← 14

    12    int result→ 14 = math_tools::doubleValue(value7);1314    std::cout << "value=" << value7 << std::endl;15    std::cout << "result=" << result14 << std::endl;16    return 0;17}
    outputvalue=7
result=14

  1. value ← 10

    9int main() {10    int value→ 10 = 10;1112    int result = math_tools::doubleValue(value10);

  2. int doubleValue(int number)

    3namespace math_tools {4int doubleValue(int number10) {5    return number10 * 2;6}

  3. result ← 20

    12    int result→ 20 = math_tools::doubleValue(value10);1314    std::cout << "value=" << value10 << std::endl;15    std::cout << "result=" << result20 << std::endl;16    return 0;17}
    outputvalue=10
result=20