的控制流程來控制程序的執(zhí)行結(jié)構(gòu)。條件表達(dá)式?jīng)Q定了執(zhí)行條件的判斷。這里我們來舉個例子說明該控制流程的工作方法。       本例通過用vb實(shí)現(xiàn)一個猜拳程序來分析條件判斷語句。首先我們先來分析一下基本的猜拳規(guī)則：1.       猜拳包括三個基本的拳（石頭，剪刀，布）2.       勝負(fù)規(guī)則：石頭>剪刀 剪刀>布 布>石頭然后我們來考慮猜拳游戲的實(shí)現(xiàn)，首先猜拳是由選手和電腦之間的比賽進(jìn)行的，電腦的猜拳我們通過隨機(jī)數(shù)來生成vb的隨機(jī)輸函數(shù)rnd函數(shù)可以生成0～1之間的隨機(jī)數(shù)我們通過int(rnd()*3)+1來實(shí)現(xiàn)生成【1～3】的隨機(jī)數(shù)，表示（石頭，剪刀，布），而選手選擇的拳記錄在變量中playerguess，然后我們再來編寫規(guī)則來實(shí)現(xiàn)。對于編寫規(guī)則我們就可以運(yùn)用到上面所介紹的條件判斷的流程控制了。通過條件判斷的流程控制我們可以做如下比較，如果電腦出（石頭，剪刀，布）的一種，選手出的（石頭，剪刀，布）的一種，那么就有9種組合規(guī)則，因此這里就需要嵌套的條件判斷。  dim guess as string    guesstimer.enabled = false    guess = randguess(int(rnd() * 3) + 1)    randlabel.caption = guess    if guess = "石頭" then        if playerguess = "rock" then            titlelabel.caption = "玩家出'石頭' 電腦出'石頭' 雙方平"            draw = draw + 1        elseif playerguess = "forfex" then            titlelabel.caption = "玩家出'布' 電腦出'石頭' 玩家贏"            win = win + 1        else 'playerguess="cloth"            titlelabel.caption = "玩家出'剪刀' 電腦出'石頭' 電腦贏"            own = own + 1        end if    elseif guess = "剪刀" then        if playerguess = "rock" then            titlelabel.caption = "玩家出'石頭' 電腦出'剪刀' 玩家贏"            win = win + 1        elseif playerguess = "forfex" then            titlelabel.caption = "玩家出'剪刀' 電腦出'剪刀' 雙方平"            draw = draw + 1        else 'playerguess="cloth"            titlelabel.caption = "玩家出'布' 電腦出'剪刀' 電腦贏"            own = own + 1        end if    else 'guess="布"        if playerguess = "rock" then            titlelabel.caption = "玩家出'石頭' 電腦出'布' 電腦贏"            own = own + 1        elseif playerguess = "forfex" then            titlelabel.caption = "玩家出'剪刀' 電腦出'布' 玩家贏"            win = win + 1        else 'playerguess="cloth"            titlelabel.caption = "玩家出'布' 電腦出'布' 雙方平"            draw = draw + 1        end if    end if    resultlabel.caption = "贏：" & win & "場" & "平：" & draw & "場" & "負(fù)：" & own & "場"

 同時我們統(tǒng)計贏，平，負(fù)的場數(shù)。

整個程序設(shè)計：

程序界面設(shè)計

程序源代碼：

 private sub clothcommand_click()    playerguess = "cloth"    guesstimer.enabled = true    titlelabel.caption = "玩家準(zhǔn)備出'布'"end sub

 private sub forfexcommand_click()    playerguess = "forfex"    guesstimer.enabled = true    titlelabel.caption = "玩家準(zhǔn)備出'剪刀'"end sub

 private sub form_load()    redim randguess(3)    randguess(1) = "石頭"    randguess(2) = "剪刀"    randguess(3) = "布"    resultlabel.caption = "贏：" & win & "場" & "平：" & draw & "場" & "負(fù)：" & own & "場"        dim sum as single    sum = 0    for i = 1 to 12        sum = sum + i    next i    msgbox sumend sub

 private sub guesscommand_click()    dim guess as string    guesstimer.enabled = false    guess = randguess(int(rnd() * 3) + 1)    randlabel.caption = guess    if guess = "石頭" then        if playerguess = "rock" then            titlelabel.caption = "玩家出'石頭' 電腦出'石頭' 雙方平"            draw = draw + 1        elseif playerguess = "forfex" then            titlelabel.caption = "玩家出'布' 電腦出'石頭' 玩家贏"            win = win + 1        else 'playerguess="cloth"            titlelabel.caption = "玩家出'剪刀' 電腦出'石頭' 電腦贏"            own = own + 1        end if    elseif guess = "剪刀" then        if playerguess = "rock" then            titlelabel.caption = "玩家出'石頭' 電腦出'剪刀' 玩家贏"            win = win + 1        elseif playerguess = "forfex" then            titlelabel.caption = "玩家出'剪刀' 電腦出'剪刀' 雙方平"            draw = draw + 1        else 'playerguess="cloth"            titlelabel.caption = "玩家出'布' 電腦出'剪刀' 電腦贏"            own = own + 1        end if    else 'guess="布"        if playerguess = "rock" then            titlelabel.caption = "玩家出'石頭' 電腦出'布' 電腦贏"            own = own + 1        elseif playerguess = "forfex" then            titlelabel.caption = "玩家出'剪刀' 電腦出'布' 玩家贏"            win = win + 1        else 'playerguess="cloth"            titlelabel.caption = "玩家出'布' 電腦出'布' 雙方平"            draw = draw + 1        end if    end if    resultlabel.caption = "贏：" & win & "場" & "平：" & draw & "場" & "負(fù)：" & own & "場"end sub

 private sub guesstimer_timer()    randlabel.caption = randguess(int(rnd() * 3) + 1)end sub

 private sub rockcommand_click()    playerguess = "rock"    guesstimer.enabled = true    titlelabel.caption = "玩家準(zhǔn)備出'石頭'"end sub

 總結(jié)：

       本程序是一個簡單易懂的vb入門程序，通過該程序使剛起步的朋友在興趣中了解程序的基本邏輯結(jié)構(gòu)同時拋開了c的機(jī)器復(fù)雜性。