如何在 c 程序或 c++ 中存储等于 10^18 的整数值？
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How to store a integer value equal to 10^18 in c programs or c++?
提问by user3599293
How can I store a large integer value in a variable of C ?
If i am declaring a with int a;it won't work.
I have used this with long long int.It is not working.
如何在 C 的变量中存储大整数值？如果我声明int a;它就行不通。我用过这个。long long int它不工作。
if( a>=0 && a <= (1000000000000000000))
What to declare variable a so that it will not so any error.It should be integer.
什么声明变量 a 以便它不会有任何错误。它应该是整数。
Compiler error
integer constant is too large for long type.
回答by yizzlez
Try a unsigned long long, assuming the value is positive, it can hold up to
尝试 a unsigned long long，假设值是正数，它可以容纳
18,446,744,073,709,551,615
(VS 13)
However, you must use the ULLsyntax.
(VS 13) 但是，您必须使用ULL语法。
回答by Nazar554
Lets look at this ifstatement you wrote:
让我们看看if你写的这个声明：
if( a>=0 && a <= (1000000000000000000))
1000000000000000000is too big for an integral literal so you will need a bigger literal type. You should declare aas an int64_tand do the comparion like that:
1000000000000000000对于整型文字来说太大了，所以你需要一个更大的文字类型。您应该声明a为 anint64_t并像这样进行比较：
if( a>=INT64_C(0) && a <= INT64_C(1000000000000000000))
Note that this will only work in a C99or C++11compiler when you #include <cstdint>or #include <stdint.h>
请注意，这只会在工作C99或C++11编译器，当你#include <cstdint>或#include <stdint.h>
Edit: in current draft of the standard you can find this sentence (2.14.2/2):
编辑：在标准的当前草案中，您可以找到这句话（2.14.2/2）：
The type of an integer literal is the first of the corresponding list in Table 6 in which its value can be represented.
整数文字的类型是表 6 中相应列表中的第一个，可以在其中表示其值。
It means that compiler should use the required literal type automatically to make your literal fit. Btw I didn't see that kind of compiler.
这意味着编译器应该自动使用所需的文字类型来使您的文字适合。顺便说一句，我没有看到那种编译器。
回答by user3599293
You can use a long longto store this integer. A long longis guranteed to hold at least 64 bits.
您可以使用 along long来存储这个整数。Along long保证至少保存 64 位。
The problem with this code: if( a>=0 && a <= (1000000000000000000))is that you need to give the literal (1000000000000000000) the suffix LLif you want it to be of type long longor ULLfor unsigned long long.
这段代码的问题if( a>=0 && a <= (1000000000000000000))是：如果你希望它是 type或for ，你需要给文字 ( 1000000000000000000) 后缀。LLlong longULLunsigned long long
