在结构测试用例设计中，有语句覆盖、条件覆盖、判定覆盖(即分支覆盖)、路径覆盖等，其(45)是最强的覆盖准则。为了对图1所示的程序段进行覆盖测试，必须适当地选取测试数据组。若x和y是两个变量，可供选择的测试数据组共有Ⅰ、Ⅱ、Ⅲ、Ⅳ四组(见表　2)，则实现判定覆盖至少应采用的测试数据组是(46)；实现条件覆盖至少采用的测试数据组是(47)，实现路径覆盖至少应采用的测试数据组是(48)或(49)。

(102)

(103)

(100)

(101)

Inside　the　computer,　the　operation　system(of　another　software　module　called　a　data　communication(71))must　decide　which　program　will　get　control　next.　Each　program　remember,　is　associated(72).　　a　particular　front　-end　port.　If　a　program's　data　have　not　yet　reached　its　front　-　end　buffer,　there　is　no　point　giving　that　program　control.　Thus　the　data　communication　monitor　sends　its　own(73)signal　to　the　front　-end　devices　next　port　is　polled.　Note　that　the(74)computer　speed.　The　computer　never　has　to　wait　for　a　terminal　or　a　communication　line.　Instead,　it　is　the　expressive　front　-　end　processor　that　waits　for　the　slower　system(75)to　respond.

(97)

(98)

(95)

(96)

Software　engineering　is　the　science　and　art　of　specifying,　designing,　implementing,　and(66)with　economy,　timeliness　and　elegance,　programs,(67)and　operating　procedures　whereby　computers　　can　be　made　useful　to　humanity.

This　definition　implicitly　sets(68)the　basic　goal　of　software　engineering　research　and　development:　　The　basic　goal　of　software　engineering　is　to　facilitate　specification,　design,　implementation　and　evolution　　of　programs,　documentation　and　operating(69)which　are　useful　to　humanity　in　an　economic,(70)and　elegant　manner(using　the　appropriate　science　and　art).