if語(yǔ)句構(gòu)建體可具有一個(gè)或多個(gè)可選的 else-if 結(jié)構(gòu)。當(dāng) if 條件不滿足,則緊跟的 else-if 被執(zhí)行。當(dāng) else-if 還是失敗,其繼續(xù)下一個(gè) else-if 語(yǔ)句(如果有的話)被執(zhí)行,依此類推。
可選的 else 被放置在末端,當(dāng)上述條件不為真時(shí)則執(zhí)行。
if...else if...else 語(yǔ)句的語(yǔ)法是:
[name:] if (logical expression 1) then ! block 1 else if (logical expression 2) then ! block 2 else if (logical expression 3) then ! block 3 else ! block 4 end if [name]
示例
program ifElseIfElseProg implicit none ! local variable declaration integer :: a = 100 ! check the logical condition using if statement if( a == 10 ) then ! if condition is true then print the following print*, "Value of a is 10" else if( a == 20 ) then ! if else if condition is true print*, "Value of a is 20" else if( a == 30 ) then ! if else if condition is true print*, "Value of a is 30" else ! if none of the conditions is true print*, "None of the values is matching" end if print*, "exact value of a is ", a end program ifElseIfElseProg
當(dāng)上述代碼被編譯和執(zhí)行時(shí),它產(chǎn)生了以下結(jié)果:
None of the values is matching exact value of a is 100