unsigned-char

问题 I need to convert a BigInteger to an unsigned integer encoded in big-endian format but I am having issues since BigInteger.toByteArray returns a signed representation. How can I convert this value to an unsigned format? (Relatively) Helpful Background I am working on some code that uses JNI to have c++ call some Java methods to handle some cryptographic functionality (this is a Microsoft CNG provider that offloads some functionality to Java). I have the public key in Java and the BigInteger

问题 Why are two char like signed char and unsigned char with the same value not equal? char a = 0xfb; unsigned char b = 0xfb; bool f; f = (a == b); cout << f; In the above code, the value of f is 0. Why it's so when both a and b have the same value? 回答1: There are no arithmetic operators that accept integers smaller than int . Hence, both char values get promoted to int first, see integral promotion for full details. char is signed on your platform, so 0xfb gets promoted to int(-5) , whereas

问题 Why are two char like signed char and unsigned char with the same value not equal? char a = 0xfb; unsigned char b = 0xfb; bool f; f = (a == b); cout << f; In the above code, the value of f is 0. Why it's so when both a and b have the same value? 回答1: There are no arithmetic operators that accept integers smaller than int . Hence, both char values get promoted to int first, see integral promotion for full details. char is signed on your platform, so 0xfb gets promoted to int(-5) , whereas

问题 Why are two char like signed char and unsigned char with the same value not equal? char a = 0xfb; unsigned char b = 0xfb; bool f; f = (a == b); cout << f; In the above code, the value of f is 0. Why it's so when both a and b have the same value? 回答1: There are no arithmetic operators that accept integers smaller than int . Hence, both char values get promoted to int first, see integral promotion for full details. char is signed on your platform, so 0xfb gets promoted to int(-5) , whereas

问题 From the following Can I turn unsigned char into char and vice versa? it appears that converting a basic_string<unsigned char> to a basic_string<char> (i.e. std::string ) is a valid operation. But I can't figure out how to do it. For example what functions could perform the following conversions, filling in the functionality of these hypothetical stou and utos functions? typedef basic_string<unsigned char> u_string; int main() { string s = "dog"; u_string u = stou(s); string t = utos(u); } I

问题 From the following Can I turn unsigned char into char and vice versa? it appears that converting a basic_string<unsigned char> to a basic_string<char> (i.e. std::string ) is a valid operation. But I can't figure out how to do it. For example what functions could perform the following conversions, filling in the functionality of these hypothetical stou and utos functions? typedef basic_string<unsigned char> u_string; int main() { string s = "dog"; u_string u = stou(s); string t = utos(u); } I

问题 From the following Can I turn unsigned char into char and vice versa? it appears that converting a basic_string<unsigned char> to a basic_string<char> (i.e. std::string ) is a valid operation. But I can't figure out how to do it. For example what functions could perform the following conversions, filling in the functionality of these hypothetical stou and utos functions? typedef basic_string<unsigned char> u_string; int main() { string s = "dog"; u_string u = stou(s); string t = utos(u); } I

问题 I am working on an assignment for creating a shell in C. The program have to read a config file, where the commands that are allowed in the shell are listed. Also in this config file, for every command that is allowed, it's sha1 checksum value is also listed. A sample line would look like this: (the file has other data too) ... other data .... * /bin/ls 3848bdeada63dc59d2117a6ca1348fe0981ad2fc When the user types a command, the program has to check if that command is in config file or not. If

问题 I am working on an assignment for creating a shell in C. The program have to read a config file, where the commands that are allowed in the shell are listed. Also in this config file, for every command that is allowed, it's sha1 checksum value is also listed. A sample line would look like this: (the file has other data too) ... other data .... * /bin/ls 3848bdeada63dc59d2117a6ca1348fe0981ad2fc When the user types a command, the program has to check if that command is in config file or not. If

问题 I am realively new to C++ so please forgive me if this is a naive question - but I'm stuck on finding an answer. I am trying to create an unsigned char array of size 1024 which I have done with the following code: unsigned char *r_record = new unsigned char[1024](); Now I have an std::string variable: std::string hw = "Hello Word"; And I would like to populate the r_record with hw (i.e., 'Hello World') starting at the 10'th byte. How can I place hw into r_record ? So in effect, my r_record