无符号字符给出错误:"expression must have a constant value"
unsigned char giving error: "expression must have a constant value"
在visualstudios中,它在这两行都给了我一个错误,说encslength
和inputslength
必须有一个常数值。
unsigned char enc_out[encslength];
unsigned char dec_out[inputslength];
然而,在我的代码中,我以前已经遇到过以下错误:
const int keylength = 256;
/* generate a key with a given length */
unsigned char aes_key[keylength / 8];
unsigned char aes_key
要求一个常数值,所以我不得不将int keylength
更改为const int keylength
当我尝试通过更改对encslength
和inputslength
执行相同操作时
size_t inputslength = strlen((const char *)aes_input);
size_t encslength = ((inputslength + AES_BLOCK_SIZE) / AES_BLOCK_SIZE) * AES_BLOCK_SIZE;
至
const size_t inputslength = strlen((const char *)aes_input);
const size_t encslength = ((inputslength + AES_BLOCK_SIZE) / AES_BLOCK_SIZE) * AES_BLOCK_SIZE;
它只是给了我一个错误:"表达式必须有一个常数值"
有人能解释一下"表达式必须有一个常数值"这两种遭遇之间的区别吗?
因为您在运行时调用函数来计算inputslength
,所以它不能是编译时常数,C++也不支持运行时可变长度数组。
有两种解决方案:使用new[]
动态分配阵列,或者使用std::vector
。我建议使用std::vector
。
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