We will learn how to work with strings in C++ in this article.<\/p>\n
A string stores a sequence of characters. In C++, there are two types of strings:<\/p>\n
1. C-style strings
\n2. Objects of the string class in the Standard C++ Library<\/p>\n
C++ continues to support C-style strings. Arrays are used to store a group of characters in C programming. C-style strings are 1-D char arrays with a null character \u2018\\0\u2019 at the end.<\/p>\n
Syntax to declare a string:<\/strong><\/p>\n Let\u2019s initialize string str to store the word TechVidvan. This can be done in the following ways:<\/p>\n Example to read and display C-style string<\/strong><\/p>\n Output<\/strong><\/p>\n Here, to read a line we used cin.get()<\/strong> function. It is used to read character arrays including whitespaces. In C++, we can represent strings as objects of std::string class. These objects are used to hold strings. The string class holds characters as a stream of bytes where we can access a single byte character.<\/p>\n Unlike character arrays, string objects do not have a fixed length and can be increased as needed.<\/p>\n Remember that to use string, we must include the <string> library as a header file in our code.<\/p>\n Syntax to declare a string object:<\/strong><\/p>\n Let\u2019s initialize a string object,<\/p>\n Example to illustrate the use of string<\/strong><\/p>\n Input<\/strong> In the above example, we have used the getline()<\/strong> function to store the string entered by the user.<\/p>\n Some other functions to operate on strings<\/p>\n 1. push_back() :<\/strong> We use this function to add a character at the end of a string. 2. pop_back() :<\/strong> We use this function to delete the last character of a string. 3. length() and size() :<\/strong> We use these functions to get the length of a string. Or<\/p>\n We know that data type char occupies 1 byte of memory space. A string in C++ thus occupies N bytes where, N = no. of characters in a string including the null character.<\/p>\n For example,<\/p>\n This string s will occupy (10 + 1) = 11 bytes of memory space. We can represent this in tabular form as shown below<\/p>\n While designing, instead of DATAFLAIR\\0, it will be TECHVIDVAN\\0 and index from 0 – 10.<\/p>\n We can use sizeof() operator to get the size of a string.<\/p>\n C++ offers various functions to operate on strings.<\/p>\n 1. strcpy<\/strong>(string1, string2); : We use this function to copy string2 into string1.<\/p>\n 2. strcat<\/strong>(string1, string2); : We use this function to concatenate both the strings.<\/p>\n 3. strlen<\/strong>(string1); : We use this function to compute the length of a string.<\/p>\n 4. strcmp<\/strong>(string1, string2); : We use this function to compare both the strings. It returns 0 when both are equal, <0 when string1<string2 and >0 when string1>string2.<\/p>\n 5. strchr<\/strong>(string1, ch); : We use this function to get the pointer pointing to the first appearance of character ch in a string.<\/p>\n 6. strrchr<\/strong>(string1, ch); : We use this function to get the pointer pointing to the last appearance of character ch in a string.<\/p>\n 7. strstr<\/strong>(string1, string2); : We use this function to get the pointer pointing to the first appearance of string2 in string1.<\/p>\n 8. strlwr<\/strong>(string1); : We use this function to convert all the characters of a string to lowercase.<\/p>\n 9. strupr<\/strong>(string1); : We use this function to convert all the characters of a string to uppercase.<\/p>\n 10. strncat<\/strong>(string1, string2, n); : We use this function to append first n characters of string2 at the end of string1.<\/p>\n 11. strncpy<\/strong>(string1, string2, n); : We use this function to copy first n characters of string2 into string1.<\/p>\n 12.strncmp<\/strong>(string1, string2, n); : We use this function to compare n characters of both the strings. It returns 0 when both are equal, <0 when\u00a0 string1<string2 and >0 when string1>string2.<\/p>\n 13. strcmpi<\/strong>(string1, string2); : We use this function to compare both the strings without considering case sensitivity. It returns 0 when both are equal, <0 when string1<string2 and >0 when string1>string2.<\/p>\n 14. strnicmp<\/strong>(string1, string2, n); : We use this function to compare n characters of both the strings ignoring case sensitivity. It returns 0 when both are equal, <0 when string1<string2 and >0 when string1>string2.<\/p>\n 15. strdup<\/strong>(string1); : We use this function to get a pointer to a duplicate string of string1.<\/p>\n 16. strndup<\/strong>(string1, n); : This function works similar to strdup except, it duplicates n characters of string.<\/p>\n 17. strset<\/strong>(string1, ch); : We use this function to set all characters of a string to character ch.<\/p>\n 18. strnset<\/strong>(string1, ch, n); : We use this function to set first n characters of a string to character ch.<\/p>\n To use these functions we need to include <string.h> header file in our program.<\/p>\n Example to illustrate the use of some C++ string functions<\/strong><\/p>\n Output<\/strong><\/p>\n Example of strings as function parameters<\/strong><\/p>\n Output<\/strong><\/p>\n In this article, we have learnt about strings in C++. A string is a sequence of characters. C++ offers us two types of strings, one in the form of character arrays and other as objects of std::string class. We discussed how to work with both the types of strings.We also learnt to pass strings to a function using example programs.<\/p>\n","protected":false},"excerpt":{"rendered":" We will learn how to work with strings in C++ in this article. A string stores a sequence of characters. In C++, there are two types of strings: 1. C-style strings 2. Objects of...<\/p>\n","protected":false},"author":1,"featured_media":81712,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3405],"tags":[3692,3693,3694,3695,3696],"class_list":["post-81409","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-cpp","tag-c-style-strings","tag-c-functions-for-strings","tag-c-string-functions","tag-memory-occupied-by-strings-in-c","tag-strings-in-c"],"yoast_head":"\nchar string_name[size];<\/pre>\n
\n
#include <iostream>\nusing namespace std;\n\nint main() {\n char word[20];\n char line[100];\n \n \/\/read a word\n cout<<\"Enter a word \";\n cin>>word;\n \/\/display the word\n cout<<endl<<word<<endl;\n \n \/\/read a line \n cout<<\"Enter a line \";\n cin.get(line, 100);\n \/\/display the line\n cout<<endl<<line;\n \n return 0;\n}\n<\/pre>\n
\nTechVidvan
\nEnter a line Articles on C++ programming
\nArticles on C++ programming<\/div>\n
\nSyntax<\/strong>:<\/p>\ncin.get(string_name, size);<\/pre>\n
Object of std::string C++ class<\/h3>\n
1. Defining a string object<\/h4>\n
string string_name;<\/pre>\n
string str = \"TechVidvan\";<\/pre>\n
#include <iostream>\n#include <string>\nusing namespace std;\n\nint main() {\n string s1;\n \n \/\/taking input of a string from user\n getline(cin, s1);\n \n \/\/displaying the string\n cout<<\"Entered string is \"<<s1;\n return 0;\n}\n<\/pre>\n
\nTechVidvan
\nOutput<\/strong><\/p>\n
\nSyntax:<\/p>\nstring_name.push_back(\u2018character\u2019);<\/pre>\n
\nSyntax:<\/p>\nstring_name.pop_back();<\/pre>\n
\nSyntax:<\/p>\nstring_name.length();<\/pre>\n
string_name.size();<\/pre>\n
Memory occupied by strings in C++<\/h3>\n
char s[ ] = \"TechVidvan\";<\/pre>\n
C++ Functions for strings<\/h3>\n
#include <iostream>\n#include <string.h>\nusing namespace std;\n\nint main() {\n char s1[ ] = \"TechVidvan\";\n char s2[ ] = \"DataFlair\";\n \n int length = strlen(s1);\n cout<<\"Length of string TechVidvan = \"<<length<<endl;\n \n char s3[15];\n strcpy(s3, s1);\n cout<<\"Copied string = \"<<s3<<endl;\n \n strcat(s1,s2);\n cout<<\"Concatenated strings = \"<<s1<<endl;\n \n if(strcmp(s1,s2)==0)\n cout<<\"Strings are equal\";\n else\n cout<<\"Strings are unequal\";\n \n return 0;\n}\n<\/pre>\n
\nCopied string = TechVidvan
\nConcatenated strings = TechVidvanDataFlair
\nStrings are unequal<\/div>\nPassing string to a function<\/h3>\n
#include <iostream>\n#include <string>\nusing namespace std;\n\nvoid print(char s[], string str) {\n cout<<\"Entered C-style string is \"<<s<<endl;\n cout<<\"Entered string object is \"<<str;\n}\nint main() {\n char s1[50] = \"TechVidvan\";\n string s2 = \"Data Flair\";\n \n print(s1, s2);\n \n return 0;\n}\n<\/pre>\n
\nEntered string object is Data Flair<\/div>\nSummary<\/h3>\n