What does ** mean in C?

In this case, double means a variable of type double. double* means a pointer to a double variable. double** means a pointer to a pointer to a double variable. In the case of the function you posted, it is used to create a sort of two-dimensional array of doubles. That is, a pointer to an array of double pointers, …

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Why does the arrow (->) operator in C exist?

I’ll interpret your question as two questions: 1) why -> even exists, and 2) why . does not automatically dereference the pointer. Answers to both questions have historical roots. Why does -> even exist? In one of the very first versions of C language (which I will refer as CRM for “C Reference Manual“, which came with 6th Edition Unix in …

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What does “dereferencing” a pointer mean?

Reviewing the basic terminology It’s usually good enough – unless you’re programming assembly – to envisage a pointer containing a numeric memory address, with 1 referring to the second byte in the process’s memory, 2 the third, 3 the fourth and so on…. What happened to 0 and the first byte? Well, we’ll get to …

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What does “dereferencing” a pointer mean?

Reviewing the basic terminology It’s usually good enough – unless you’re programming assembly – to envisage a pointer containing a numeric memory address, with 1 referring to the second byte in the process’s memory, 2 the third, 3 the fourth and so on…. What happened to 0 and the first byte? Well, we’ll get to …

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“Char cannot be dereferenced” error

I’m trying to use the char method isLetter(), which is supposed to return boolean value corresponding to whether the character is a letter. But when I call the method, I get an error stating that “char cannot be dereferenced.” I don’t know what it means to dereference a char or how to fix the error. …

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“Char cannot be dereferenced” error

The type char is a primitive — not an object — so it cannot be dereferenced Dereferencing is the process of accessing the value referred to by a reference. Since a char is already a value (not a reference), it can not be dereferenced. use Character class: