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When I declare a variable, such as:
int x = 6;
What exactly is x? an address in the memory is usually hexadecimal..
Also, when I'm calling X
x = 2;
How does the compiler know where x is? x isn't an address.
That was my first question.
Second:
Let's say i have an object:Person p;p has 2 datamembers:
int type1, int type2;
What exactly is p, and why do I need to go to p, then the variable?
p.type1, p->type1.
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type variableName = value; Where type is one of C types (such as int ), and variableName is the name of the variable (such as x or myName). The equal sign is used to assign a value to the variable.
In C language, a variable name can consists of letters, digits and underscore i.e. _ . But a variable name has to start with either letter or underscore. It can't start with a digit. So valid variables are var_9 and _ from the above question.
When we create a variable in a C program, the C compiler allocates a storage space, depending upon the datatype of the variable(8 bits for char , 16/32 bits for int , etc.), and then that storage space is given a name which is the variable name.
In the case int x = 6, x is just a name to help you write the code and the compiler compile it. It's basically an alias for some place in memory, so that it's easier to access it later via x = 2 - this tells both you and the compiler that you want to write the value 2 in that same place.
Same as before, but it takes up more space (sizeof(Person) to be exact). p->type1 is only valid if p is a pointer to a Person (or if you overloaded the -> operator, but it's not the case), p.type1 is the syntax used for an object, to specify which part of the it you want to access.
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int x=6 ;
Here x is identifier i.e. the name given to memory area where value 6 is stored.x is simple name just to identify memory area where value 6 is stored.
when u declares variable, that time compiler stores ur variable name in the identifier table.
For person p, here once again p is name given to the memory area,which stores two data member type1 & type2
For accessing the value of type1 & type2, first u have to find the memory area, where they are stored. That's why u have to first access the memory area p & then u can access type1 * type2
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