虽然有可能将外链很多！

虽然有可能将外链很多，如果其他语句在一起，这是很难读。考虑以下程序：

enum
Colors

{

    COLOR_BLACK,

    COLOR_WHITE,

    COLOR_RED,

    COLOR_GREEN,

    COLOR_BLUE

};

 

void
printColor(Colors
color)

{

    if
(color
==
COLOR_BLACK)

        std::cout
<<
"Black";

    else
if
(color
==
COLOR_WHITE)

        std::cout
<<
"White";

    else
if
(color
==
COLOR_RED)

        std::cout
<<
"Red";

    else
if
(color
==
COLOR_GREEN)

        std::cout
<<
"Green";

    else
if
(color
==
COLOR_BLUE)

        std::cout
<<
"Blue";

    else

        std::cout
<<
"Unknown";

}
因为如果平等在单变量测试其他的链是很常见的，C++提供了一种替代的条件分支的操作称为开关。这里是相同的程序，如开关形式：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

void printColor(Colors color) {     switch (color)     {         case COLOR_BLACK:             std::cout << "Black";             break;         case COLOR_WHITE:             std::cout << "White";             break;         case COLOR_RED:             std::cout << "Red";             break;         case COLOR_GREEN:             std::cout << "Green";             break;         case COLOR_BLUE:             std::cout << "Blue";             break;         default:             std::cout << "Unknown";             break;     } }