String processing techniques in C++

In C, string (string) is a very common data type. Moreover, string processing is also a very important link in programming. This article will introduce some commonly used string processing techniques in C, hoping to be helpful to readers.

1. String class in C

In C, string is a class, included in the header file . There are many member functions in the string class. Here are some commonly used member functions:

1. append() function: used to add one string to the end of another string.

For example:

string str1 = "Hello";

string str2 = "World";

str1.append(str2);

cout

2. length() function: used to obtain the length of a string.

For example:

string str = "Hello World";

int len ​​= str.length(); //The value stored in the len variable is 11

3. substr() function: used to intercept part of a string.

For example:

string str = "Hello World";

string s = str.substr(6, 5); //From the 6th character of the string Start, intercept the substring of length 5

cout

4, erase() function: used to delete strings part.

For example:

string str = "Hello World";

str.erase(5, 6); //Delete the length starting from the 5th character in the string It is a substring of 6

cout

2. String traversal

1. Use subscripts Access:

Use subscripts to access each element of the string.

For example:

string str = "Hello World";

for (int i = 0; i

cout << str[i] << " ";

}

The output result is:

H e l l o W o r l d

2. Use iterator:

Use iterator in C ( iterator), which can easily traverse strings.

For example:

string str = "Hello World";

for (string::iterator it = str.begin(); it != str.end() ; it) {

cout << *it << " ";

}

The output result is:

H e l l o W o r l d

3. Splitting and merging strings

1. String splitting:

You can use objects of the stringstream class to split the string according to a certain delimiter.

For example:

string str = "Hello World, This is a good day!";

stringstream ss(str);

string s;

while (getline(ss, s, ',')) {

cout << s << endl;

}

The output result is:

Hello World

This is a good day!

2. String merging:

You can use objects of the stringstream class to merge multiple strings.

For example:

stringstream ss;

string s1 = "Hello";

string s2 = "World!";

ss

string s = ss.str();

cout

The output result is:

Hello World!

IV. Other commonly used functions

1. atoi() function:

Convert strings to integers .

For example:

char a[] = "1234";

int b = atoi(a);

cout

2. atof() function:

Convert a string into a floating point number.

For example:

char a[] = "12.34";

float b = atof(a);

cout

3. strcmp() function:

Compare the sizes of two strings.

For example:

char str1[] = "Hello";

char str2[] ​​= "World";

int res = strcmp(str1 , str2);

cout

4, strstr() function:

Find in the string Contains another string.

For example:

char haystack[] = "Hello World";

char needle[] = "Wo";

char *res = strstr (haystack, needle);

cout

Note: The return value is a pointer to the first occurrence of the substring.

The above are commonly used string processing techniques in C. I hope they can help everyone. Of course, there are many other techniques and functions that can be used to process strings, which require continuous learning and practice.

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