換句話說,
a>=b
等同于
a==b||a>b
還是
a>b||a==b?
如果等于這個,程序會更慢,我覺得應(yīng)該等同于a == b || a > b才對。
That's not true. Your platform will not split >= into == and >. The implementation varies from platform to platform and compiler to compiler. From Assembly(https://godbolt.org/g/6MCvQq):
if (a >= b)
=>
mov eax, dword ptr [rbp - 12]
cmp eax, dword ptr [rbp - 16]
jl .LBB0_4
if (a > b)
=>
cmp r8d, dword ptr [rbp - 16]
mov dword ptr [rbp - 20], eax # 4-byte Spill
jle .LBB0_2
Both have 3 instructions.
Also take a look at these awesome answers: https://stackoverflow.com/que...
Both are true. || is logic or operator in some languages(which belongs to logic operators). I assume you have limited the symbols to c++(because you didn't use the more general terms like logic or and logic and. In standard ml, logic or is expressed as or, same for logic and)
In c++, please correct = to ==. The former is a Direct assignment operator, while the latter is Equal to operator. If a satisfy the condition, the b will not be used. For example:
if (a && b)
is equal to
if (a)
if(b)
...
BTW, in some algorithms, if you want to judge if a node exists (like arr[x][y] == 'x'), it should be put in b rather than a. Because sometimes a is used to filter out-of-range conditions.
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