Solutions to string processing problems in C++

Solutions to string processing problems in C

Overview:
In C programming, string processing is a common problem involving characters String interception, splicing, search, replacement and other operations. This article will introduce several common solutions and provide specific code examples.

1. String interception
String interception refers to obtaining a part of a substring from a string. In C, you can use the substr() function to implement string interception.

The following is a sample code that demonstrates how to use the substr() function to intercept part of a string:

#include <iostream>
#include <string>

int main() {
    std::string str = "Hello, world!";
    std::string substr = str.substr(7, 5); // 从位置7开始，截取长度为5的子串
    std::cout << substr << std::endl; // 输出：world
    return 0;
}

2. String splicing
String splicing refers to combining multiple characters Strings are concatenated into one string. In C, you can use the operator or the append() function to implement string concatenation.

The following is a sample code that demonstrates how to use operators and append() functions to splice strings:

#include <iostream>
#include <string>

int main() {
    std::string str1 = "Hello, ";
    std::string str2 = "world";
    std::string str3 = str1 + str2; // 使用+运算符拼接字符串
    std::cout << str3 << std::endl; // 输出：Hello, world

    std::string str4 = "Hello, ";
    std::string str5 = "world";
    str4.append(str5); // 使用append()函数拼接字符串
    std::cout << str4 << std::endl; // 输出：Hello, world

    return 0;
}

3. String search
String search refers to searching in a Searches for the specified substring in a string and returns the position of the substring in the string. In C, you can use the find() function to implement string search operations.

The following is a sample code that demonstrates how to use the find() function to find a substring:

#include <iostream>
#include <string>

int main() {
    std::string str = "Hello, world!";
    std::string sub = "world";
    size_t found = str.find(sub); // 查找子串在字符串中的位置
    if (found != std::string::npos) {
        std::cout << "子串的位置：" << found << std::endl; // 输出：子串的位置：7
    } else {
        std::cout << "未找到子串" << std::endl;
    }

    return 0;
}

4. String replacement
String replacement refers to replacing a string in Replace a substring of with another string. In C, you can use the replace() function to implement string replacement operations.

The following is a sample code that demonstrates how to use the replace() function to replace a substring:

#include <iostream>
#include <string>

int main() {
    std::string str = "Hello, world!";
    std::string old_sub = "world";
    std::string new_sub = "everyone";
    size_t found = str.find(old_sub); // 查找子串的位置
    if (found != std::string::npos) {
        str.replace(found, old_sub.length(), new_sub); // 替换子串
        std::cout << str << std::endl; // 输出：Hello, everyone!
    } else {
        std::cout << "未找到子串" << std::endl;
    }

    return 0;
}

Summary:
This article introduces common solutions to string processing problems in C , including string interception, splicing, search and replacement. The above code example shows how to use string processing functions to implement these operations. For C beginners, mastering these string processing methods will be of great help in future programming work. At the same time, readers can also call and expand related functions according to actual needs to further improve their string processing capabilities.

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