Souvik Das

Hello Ishwari
We know we have already defined data types like int, char, float, double.
Let's take int
When we declare
int i ;
It simply means an area of 2 Bytes(architecture dependent) gets allocated and the area is named as i and as our houses get some address in a street, in the same manner, this area will also have an address.

Now if we want some area which must contain say some 5 Bytes and that area has to be divided into 3 areas.
we want to give the first division to an int , the 2nd division to a char, the 3rd division to another int.
So this type of data type is not already defined.

So we need to make a data type like this on our own.

How to do that?
We use structure.

struct datatype
{
    int i;
    char c;
    int j;
};

Now if we declare
datatype x;
Then x will have our desired memory allocation.


Math.h 
has function definitions of the mathematical functions that we use.
example : pow()

Similarly, string.h has functions that we use t manipulate strings. 
 

Hello Chirra
Think it this way, we can't precisely pinpoint when we started to learn our mother tongue, but we are quite comfortable in it.
Again if we think, we started to learn English in our school days, and we were made to understand and make correct usage of grammar. Right!!!
Similar is the case with C, C++, Java or any other language that we want to learn.
You have to learn the grammar of the language, i.e. the rules by which you can write a sentence in C language.
Then slowly we got to start writing a few correct sentences which make some meaning.
Then we will automatically try to write prose(called functions in C) or paragraphs(modules/collections of codes) using C language.
That's all. Once you start using it to express your thoughts, you will begin to look for its betterment(called algorithm analysis in terms of programming.)
And we all know there is no limit to improvement.
All the best!

Everyone has one's style of grooving into different terrains. One might like to go to hill stations, and another might want to go to the forest for a vacation.
Similar is the case here. I would suggest to take a demo class of both the online platforms and the physical classrooms, in whichever mode you feel comfortable, opt for that.
It is you who have to assimilate the concepts properly.
All the best.

For Mathematics and Science, it would be Rs300-400  per class depending on the experience of the teacher.

For English, it would be Rs250-400 per class, depending on the experience and expertise of the teacher.

NOTE: The price depends on the cost of living of the location.