The language specification is where null is defined, and it says There is also a special null type, the type of the expression null, which has no name. Because the null type has no name, it is impossible to declare a variable of the null type or to cast to the null type. The null … Read more
The easiest way to for-each every char in a String is to use toCharArray(): This gives you the conciseness of for-each construct, but unfortunately String (which is immutable) must perform a defensive copy to generate the char[] (which is mutable), so there is some cost penalty. From the documentation: [toCharArray() returns] a newly allocated character array whose length is the length of this string and whose contents are … Read more
haracters are extracted until either (n – 1) characters have been extracted or the delimiting character is found (which is delimiter if this parameter is specified, or ‘\n’ otherwise). The extraction also stops if the end of the file is reached in the input sequence or if an error occurs during the input operation. When cin.getline() reads … Read more
Notice you’re not dynamically allocating the variable, which pretty much means the data inside str, in your function, will be lost by the end of the function. You should have: Then, when you call the function, the type of the variable that will receive the data must match that of the function return. So, you should … Read more
A char variable is actually an 8-bit integral value. It will have values from 0 to 255. These are almost always ASCII codes, but other encodings are allowed. 0 stands for the C-null character, and 255 stands for an empty symbol. So, when you write the following assignment: It is the same thing as this on an ASCII system. So, you can compare two char variables using … Read more
The character ‘\’ is a special character and needs to be escaped when used as part of a String, e.g., “\”. Here is an example of a string comparison using the ‘\’ character: You can also perform direct character comparisons using logic similar to the following:
If you just want to pass a std::string to a function that needs const char* you can use If you want to get a writable copy, like char *, you can do that with this: Edit: Notice that the above is not exception safe. If anything between the new call and the delete call throws, you will leak memory, as nothing will call delete for you … Read more
Use chr() and ord():
It won’t automatically convert (thank god). You’ll have to use the method c_str() to get the C string version. Note that it returns a const char *; you aren’t allowed to change the C-style string returned by c_str(). If you want to process it you’ll have to copy it first: Or in modern C++:
Use chr() and ord():