{"id":209,"date":"2020-08-31T08:13:26","date_gmt":"2020-08-31T08:13:26","guid":{"rendered":"https:\/\/www.kindsonthegenius.com\/cplusplus\/?p=209"},"modified":"2020-08-31T08:13:26","modified_gmt":"2020-08-31T08:13:26","slug":"c-string-manipulation","status":"publish","type":"post","link":"https:\/\/www.kindsonthegenius.com\/cplusplus\/c-string-manipulation\/","title":{"rendered":"C++ String Manipulation"},"content":{"rendered":"

In this lesson, you will learn about string manipulation in C++. We’ll cover all the various operations that you can do with strings.<\/p>\n

    \n
  1. C-Type Strings<\/a><\/li>\n
  2. C++ String Object<\/a><\/li>\n
  3. String Manipulation Functions from C<\/a><\/li>\n
  4. String Manipulation with C++ String Class<\/a><\/li>\n<\/ol>\n

     <\/p>\n

    1. C-Type Strings<\/strong><\/h4>\n

    As you know, C++ supersets the C language. Therefore, it supports string functionalities from C. This is also called C-String. Strings in C are 1-dimensional array<\/a> of characters that is terminated by a null character, ‘\\0’ (ASCII code for 0).<\/p>\n

    To define a C-string in C++ use the code below;<\/p>\n

    char<\/span> name[] =<\/span> \"Kindson\"<\/span>;\r\n<\/pre>\n
    In the code above, the string name is created and holds 7 characters.<\/p>\n
    char<\/span> str[4<\/span>] =<\/span> \"Kindson\"<\/span>;\r\n\t \r\nchar<\/span> str[] =<\/span> {'K'<\/span>,'i'<\/span>,'n'<\/span>, 'd'<\/span>, 's'<\/span>, 'o'<\/span>, 'n'<\/span>, '\\0'<\/span>};\r\n\r\nchar<\/span> str[4<\/span>] =<\/span> {'H'<\/span>,'e'<\/span>,'l'<\/span>, 'l'<\/span>, 'o'<\/span>, '\\0'<\/span>};\r\n<\/pre>\n
    The program below uses a C-type string to read a name from the input. Then displays the name to the output.<\/p>\n
    int<\/span> main<\/span> () {\r\n\t\/\/you must provide a size<\/span>\r\n\tchar<\/span> name[20<\/span>];\r\n\tcout <<<\/span> \"Please enter your name: \"<\/span>;\r\n\tcin >><\/span> name;\r\n\tcout <<<\/span> \"Hello \"<\/span> <<<\/span> name <<<\/span> endl;\r\n}\r\n<\/pre>\n
     <\/p>\n
    2. C++ String Object<\/strong><\/h4>\n
    C++ also provides it’s own string class. So you can create string object. This class is provided by the standard C++ library. Unlike character array from C, the C++ string does not have a fixed length.\u00a0 For example, the code below, reads and prints the user’s name but without knowing the size of the name:<\/p>\n
    \/\/ Example with C++ String<\/span>\r\nint<\/span> main<\/span> () {\r\n\t\/\/ size is not needed<\/span>\r\n\tstring name;\r\n\tcout <<<\/span> \"What is your name: \"<\/span>;\r\n\tcin >><\/span> name;\r\n\tcout <<<\/span> \"Welcome \"<\/span> <<<\/span> name <<<\/span> endl;\r\n}\r\n<\/pre>\n
     <\/p>\n
    3. String Manipulation Methods (from C)<\/strong><\/h4>\n
    These are methods used for string manipulation. You need to understand these functions to be get things done with strings.<\/p>\n
    See table below:<\/p>\n\n\n\n\n\n\n\n\n\n
    SN<\/th>\nMethod and description<\/th>\n<\/tr>\n
    1<\/td>\nstrcpy(string1, string2)<\/b><\/p>\n
    Copies string string2 into string string1.<\/td>\n<\/tr>\n
    2<\/td>\nstrcat(string1, string2)<\/b><\/p>\n
    Concatenates string string2 onto the end of string string1.<\/td>\n<\/tr>\n
    3<\/td>\nstrlen(string1)<\/b><\/p>\n
    Returns the length of string string1.<\/td>\n<\/tr>\n
    4<\/td>\nstrcmp(string1, string2)<\/b><\/p>\n
    Returns 0 if string1 and string2 are the same; less than 0 if string1<string2; greater than 0 if string1 > string2.<\/td>\n<\/tr>\n
    5<\/td>\nstrchr(string1, ch);<\/b><\/p>\n
    Returns a pointer to the first occurrence of character ch in string string1.<\/td>\n<\/tr>\n
    6<\/td>\nstrstr(s1, s2)<\/b><\/p>\n
    Returns a pointer to the first occurrence of string string2 in string string1.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
    The functions above derives from C. Therefore to use them, you need to include <cstring> header in your program.<\/p>\n
     <\/p>\n
    4. String Manipulation With C++ String Class<\/strong><\/h4>\n
    Let’s now see how to do the same thing using C++ string class<\/p>\n
      \n
    • Concatenation<\/strong> – Combines two string into one. Simply use the + operator<\/strong><\/em>. See example below<\/li>\n
    • String length<\/strong> – Use length()<\/strong><\/em> method<\/li>\n
    • Searching strings<\/strong> – Accessing a character within a string. Use the find()<\/strong> method<\/li>\n
    • Substrings<\/strong> – Returning part of a string. Use the substr()<\/em><\/strong> method.<\/li>\n
    • Replacing<\/strong> – Replacing part of a string. Use the replace()<\/em><\/strong> method<\/li>\n
    • Insertion<\/strong> – Inserting character(s) into a string. Using the insert()<\/strong><\/em> method<\/li>\n
    • Erase<\/strong> – Removing part of a string. Use the erase()<\/em><\/strong> method.<\/li>\n<\/ul>\n
      The program below shows how these methods can be applied.<\/p>\n
      \/\/ String manipulation using methods<\/span>\r\nint<\/span> main<\/span> () {\r\n\t   string string1 =<\/span> \"Beginner \"<\/span>;\r\n\t   string string2 =<\/span> \"to Expert \"<\/span>;\r\n\t   string string3 =<\/span> \"Tutorials\"<\/span>;\r\n\t   string string4 =<\/span> string1 +<\/span> string2 +<\/span> string3;\r\n\t   int<\/span>  len =<\/span> string4.length();\r\n\r\n\r\n\t   cout <<<\/span> string4 <<<\/span> endl;\r\n\r\n\t   cout <<<\/span> \"Length of string1 is: \"<\/span> <<<\/span> len <<<\/span>endl;\r\n\r\n\t   cout <<<\/span>\"Expert is at position \"<\/span> <<<\/span> string2.find(\"Expert\"<\/span>) <<<\/span>endl;\r\n\r\n\t   cout <<<\/span> \"Part of string 2: \"<\/span> <<<\/span> string2.substr(3<\/span>,8<\/span>)<<<\/span>endl;\r\n\r\n\t   cout <<<\/span> \"Replacing 'Expert':  \"<\/span> <<<\/span> string4.replace(12<\/span>, 17<\/span>, \"Guru\"<\/span>)<<<\/span>endl;\r\n\r\n\t   cout <<<\/span> \"Insertion:  \"<\/span><<<\/span> string4.insert(0<\/span>, \" by Kindson\"<\/span>)<<<\/span>endl;\r\n\r\n\t   cout <<<\/span> \"Erasing:  \"<\/span> <<<\/span> string3.erase(0<\/span>,3<\/span>)<<<\/span>endl;\r\n\r\n\t   return<\/span> 0<\/span>;\r\n}\r\n<\/pre>\n
      If you successfully run the program, you will have the output:<\/p>\n
      Beginner to Expert Tutorials\r\nLength of string1 is: 28\r\nExpert is at position3\r\nPart of string 2: Expert \r\nReplacing 'Expert':  Beginner to Guru\r\nInsertion:   by KindsonBeginner to Guru\r\nErasing:  orials\r\n<\/pre>\n
      I would recommend you take some time to understand how it works to produce the outputs.<\/p>\n","protected":false},"excerpt":{"rendered":"
      In this lesson, you will learn about string manipulation in C++. We’ll cover all the various operations that you can do with strings. C-Type Strings … <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-209","post","type-post","status-publish","format-standard","hentry","category-c-tutorials"],"_links":{"self":[{"href":"https:\/\/www.kindsonthegenius.com\/cplusplus\/wp-json\/wp\/v2\/posts\/209","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.kindsonthegenius.com\/cplusplus\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.kindsonthegenius.com\/cplusplus\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.kindsonthegenius.com\/cplusplus\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.kindsonthegenius.com\/cplusplus\/wp-json\/wp\/v2\/comments?post=209"}],"version-history":[{"count":1,"href":"https:\/\/www.kindsonthegenius.com\/cplusplus\/wp-json\/wp\/v2\/posts\/209\/revisions"}],"predecessor-version":[{"id":210,"href":"https:\/\/www.kindsonthegenius.com\/cplusplus\/wp-json\/wp\/v2\/posts\/209\/revisions\/210"}],"wp:attachment":[{"href":"https:\/\/www.kindsonthegenius.com\/cplusplus\/wp-json\/wp\/v2\/media?parent=209"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.kindsonthegenius.com\/cplusplus\/wp-json\/wp\/v2\/categories?post=209"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.kindsonthegenius.com\/cplusplus\/wp-json\/wp\/v2\/tags?post=209"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}