Working With String

Append

As you saw in the previous chapter, we cannot add new characters to the end of a string using indexing. But C++ has a neat .append() method for that. Here is the syntax:

Concatenate

Another way to do it is by using the + operator.
It performs concatenation when applied to strings. Here is an example:

main


              12345678
            
#include <iostream>

int main()
{
    std::string str = "Code";
    str = str + "finity"; // or str += "finity"
    std::cout << str << std::endl;
}

It also allows adding text to the beginning or to both ends, which .append() is incapable of.

main


              12345678
            
#include <iostream>

int main()
{
    std::string str = "finity";
    str = "code" + str + ".com";
    std::cout << str << std::endl;
}

Insert

You can also insert new text to a string at a desired position.
Here is the syntax:

Where pos is an index, before which, new text is inserted.

Here is a gif of how insertion works:

Replace

You can also replace a part of a string with a different string.
This is achievable using the .replace() method. Here is the syntax:

Here start means the index of the first element to replace, and n stands for the length of a part to replace.

The following is a gif of how .replace() works.

Erase

You can also erase part of a string. Here is the syntax:

start and n parameters have the same meaning as in the .replace() method.

In this chapter, you learned

Here is an example of using all of the methods.

main


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#include <iostream>

int main()
{
    std::string str = "finity";
    
    str.append(".com"); // finity to finity.com
    std::cout << str << std::endl;
    
    str = "in" + str; // finity.com to infinity.com
    std::cout << str << std::endl;
    
    str.insert(2, "de"); // infinity.com to indefinity.com
    std::cout << str << std::endl;
    
    str.replace(0, 2, "co"); // indefinity.com to codefinity.com
    std::cout << str << std::endl;
    
    str.erase(10, 4); // codefinity.com to codefinity
    std::cout << str << std::endl;
}

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