Get Char from String at Specific Index in C++

If you have to write your own algorithm for operating on strings, don’t use a basic_string like you would a C-style string by using operator[] to get at each item. Each of the find functions takes a size_type parameter that indicates the index where the search should proceed from. Using the find functions repeatedly, pronounce azazel you can advance through the string as you see fit. Consider Example 4-16, which counts the number of unique characters in a string. A sub-string or substring or range is just a portion of a sequence of characters within the string literal. Knowing what a substring is in C++ is not sufficient for a programmer.

This implies that if we give multi-input words to a string then the string will store and display only one word and omits all the words after the first space. Cin keyword is programmed as when there is space it considers it as a terminating character. For calculating the length of C style strings strlen() function is used. When the strcat function is used the s1 string is concatenated with the s2 string and stored in s1. This means that s1 is updated and s2 remains the same as its previous content.

Further, we have traversed through the string of x char array till the pointer variable p points to the index of the last character of x. Same as 2 D array of integers and other data types, we have 2 D array of characters also. Note that in the above example, we gave array size to s1 because we are adding the characters of another string to it. The array size given should be such that it is greater than or equal to the size of the string array after concatenation. Cin.getline(name, sizeof); – cin.getline takes two arguments, the string variable and the size of that variable.

As a next step, we have declared and initialized a string. Then, we gained access to every character of the string in reverse order by writing a negative sign which indicates them from last to second to last, and so on. C++ defines a way to use string objects for holding strings, i.e, we use string data type for creating strings. Npos can be added to this iterator to point to the last element of the range. The last element or last character of the range is not part of the substring.

The strrchr returns the last occurrence of a character within a string. They return a character pointer to the character found, or NULL pointer if the character is not found. If pos is equal to the string length, the function returns a reference to the null character that follows the last character in the string .

String name is a string object which has many data members. The data member of name i.e. p is a pointer to the first character in an array of characters which are dynamically allocated. The data member of name i.e. length contains the length of the string name. The data member of name i.e. capacity contains the number of valid characters in string name which are stored in the array. Function only accepts character arrays as its arguments.