Strings in C++

-
Strings are character arrays whose last value is '\0', null character.

 You can define a string as :
 char str[] = {'h', 'e', 'y', '\0' }
or as 
 char str[] = "hey";  // str can be modified
or as
 char * str = "hey"; // str cannot be modified, will cause segmentation error
 const char * str2 = "heyy"; // will not cause warning, still cannot modify
or by using the string data type
 string s = "hey";

The string class, included as #include <string> provides various functions to perform string operations. Some of them are :

 strlen(str) -> length of str

 strcat(str1,str2) -> concatenate str2 at the end of str1

 strcpy(str1,str2) -> copy str2 into str1

When you declare as char[int] then you cannot directly assign value using = rather you need to use strcpy

Comments

Post a Comment

Popular posts from this blog

In Place Algorithms

-
I n-Place Algorithms are required to solve those problems which have limited memory constraints. You are not allowed to use extra memory and hence all operations need to be performed on the original data structures themselves. Usually, the algorithms should use O(1), constant memory. You are allowed to declare variables but not complete data structures. For example, you are given an array [1,2,2,4] and you need to delete all values which are equal to 2. One approach could be by checking each element of the array. If it is 2 then skip otherwise store the value in a new array and at the end of the loop[ when traversed every element of array ], return the new array. But this approach is not In-Place as it requires O(n) memory [ Worst case when no element of given value in array ]. For an In-Place algorithm we would need to delete the elements with value in the original array and then return the original array as the answer to the problem. 
Read more

References in C++

-
References in C++ are very important as they can help you significantly reduce the running time of your code. A reference is simply another name to the same data value. For example, here x_ref is a integer reference to x : int x = 10; int & x_ref = x; // reference initialization cout<<x_ref; // x_ref and x are same, i.e. 10 x_ref = 20; cout<<x; // x is now 20 A reference is declared by using the & sign [the & sign is also used to get memory location of a variable].  It is necessary to initialize a reference at the time it is declared. It is because you cannot have NULL references, so you need to initialize an explicit value to which declared reference is a reference to.  When you modify a reference, the original value also changes. Another example, string s = "Hello, this is original string"; string &x = s; x = "Modified string"; cout<<x; // outputs Modified string cout<<s; // outputs Modi...
Read more