3循环的嵌套 一个循环体内又包含了一个完整的循环结构称为循环的嵌套.1 例413打印九九乘法表 For i= 1 to 9 For j=1 To 9 AL. For j=1 To i22 se=i&"×"&j&"="&i*j Picture1 Print Tab((j-1)*9+1); se; Next j Picture Print La Next i h×1=11×2=21×3=-31X 1X5=51X6=61×7=71×8=81×9=9 1=22×2=42X3=62×4=82×5=102×6=122×7=142×8=162×9-18 3×1=33×2=63×3=93×4=123×5=153×6=183×7=213×8=243×9=27 41=44X2=84×3=124×4164×5=204×6=244×7=284X8=324×9=36 1=55×2-105×3=155×4=205×5=255×6=305×7=355×8=405×9=45 ×1=66×2=126×3=186×4=246×5=306X6=366×7=426X8=486×9=54 1=77×2-147×3=217X4=287×5=357×6=427x7=497X8=567×9=63 3×1=88×2=168×3=248×4=328X5=408×6=488×7=568×8=648×9=72 1=99×2=189×3=279×4=369×5=459×6=549×7=639×8=729×9=81 思考:打印上三角或下三角程序如何改动?要打印下三角?3.循环的嵌套 一个循环体内又包含了一个完整的循环结构称为循环的嵌套. 例4.13打印九九乘法表. For i = 1 To 9 For j = 1 To 9 For j = 1 To i se = i & "×" & j & "=" & i * j Picture1.Print Tab((j - 1) * 9 + 1); se; Next j Picture1.Print Next i 思考：打印上三角或下三角程序如何改动？要打印下三角?