检查给定的字符串是否是注释

给定一个字符串S ，代表程序中的一行，任务是检查给定的字符串是否是注释。

Types of comments in programs:

• Single Line Comment: Comments preceded by a Double Slash (‘//’)
• Multi-line Comment: Comments starting with (‘/*’) and ending with (‘*/’).

例子：

Input: line = “/*GeeksForGeeks GeeksForGeeks*/” 
Output: It is a multi-line comment

Input: line = “// GeeksForGeeks GeeksForGeeks” 
Output: It is a single-line comment 

方法：想法是检查输入的字符串是否是注释。以下是步骤：

• 检查第一个索引(即索引 0)的值是否为 ‘/’ 然后按照以下步骤操作，否则打印“It is not a comment”。
• 如果行 [0] == ‘/’：
  • 如果 line[1] == ‘/’，则打印“It is a single line comment”。
  • 如果 line[1] == ‘*’，则遍历字符串，如果找到任何相邻的 ‘*’ & ‘/’ 对，则打印“It is a multi-line comment”。
• 否则，打印“这不是评论”。

下面是上述方法的实现：

C++

// C++ program for the above approach
 
#include 
using namespace std;
 
// Function to check if the given
// string is a comment or not
void isComment(string line)
{
 
    // If two continuous slashes
    // preceeds the comment
    if (line[0] == '/' && line[1] == '/'
        && line[2] != '/') {
 
        cout << "It is a single-line comment";
        return;
    }
 
    if (line[line.size() - 2] == '*'
        && line[line.size() - 1] == '/') {
 
        cout << "It is a multi-line comment";
        return;
    }
 
    cout << "It is not a comment";
}
 
// Driver Code
int main()
{
    // Given string
    string line = "/*GeeksForGeeks GeeksForGeeks*/";
 
    // Function call to check whether then
    // given string is a comment or not
    isComment(line);
 
    return 0;
}

Java

// Java program for the above approach
import java.io.*;
import java.lang.*;
import java.util.*;
 
class GFG{
 
// Function to check if the given
// string is a comment or not
static void isComment(String S)
{
    char line[] = S.toCharArray();
 
    // If two continuous slashes
    // preceeds the comment
    if (line[0] == '/' && line[1] == '/' &&
        line[2] != '/')
    {
        System.out.println(
            "It is a single-line comment");
        return;
    }
 
    if (line[line.length - 2] == '*' &&
        line[line.length - 1] == '/')
    {
        System.out.println(
            "It is a multi-line comment");
        return;
    }
 
    System.out.println("It is not a comment");
}
 
// Driver Code
public static void main(String[] args)
{
     
    // Given string
    String line = "/*GeeksForGeeks GeeksForGeeks*/";
 
    // Function call to check whether then
    // given string is a comment or not
    isComment(line);
}
}
 
// This code is contributed by Kingash

Python3

# Python3 program for the above approach
 
# Function to check if the given
# string is a comment or not
def isComment(line):
   
    # If two continuous slashes
    # preceeds the comment
    if (line[0] == '/'  and line[1] == '/' and line[2] != '/'):
        print("It is a single-line comment")
        return
 
    if (line[len(line) - 2] == '*' and line[len(line) - 1] == '/'):
        print("It is a multi-line comment")
        return
 
    print("It is not a comment")
 
# Driver Code
if __name__ == '__main__':
   
    # Given string
    line = "/*GeeksForGeeks GeeksForGeeks*/"
     
    # Function call to check whether then
    # given string is a comment or not
    isComment(line)
     
    # This code is contributed by ipg2016107.

C#

// C# program for the above approach
using System;
using System.Collections.Generic;
 
class GFG{
     
// Function to check if the given
// string is a comment or not
static void isComment(string S)
{
    char[] line = S.ToCharArray();
 
    // If two continuous slashes
    // preceeds the comment
    if (line[0] == '/' && line[1] == '/' &&
        line[2] != '/')
    {
        Console.WriteLine("It is a single-line comment");
        return;
    }
 
    if (line[line.Length - 2] == '*' &&
        line[line.Length - 1] == '/')
    {
        Console.WriteLine("It is a multi-line comment");
        return;
    }
 
    Console.WriteLine("It is not a comment");
}
 
// Driver Code
static public void Main()
{
     
    // Given string
    string line = "/*GeeksForGeeks GeeksForGeeks*/";
 
    // Function call to check whether then
    // given string is a comment or not
    isComment(line);
}
}
 
// This code is contributed by splevel62

Javascript

 
// JavaScript program for the above approach
  
 
// Function to check if the given
// string is a comment or not
function isComment( line)
{
 
 
    // If two continuous slashes
    // preceeds the comment
    if (line[0] == '/' && line[1] == '/' &&
        line[2] != '/')
    {
        document.write(
            "It is a single-line comment");
        return;
    }
 
    if (line[line.length - 2] == '*' &&
        line[line.length - 1] == '/')
    {
        document.write(
            "It is a multi-line comment");
        return;
    }
 
    document.write("It is not a comment");
}
// Driver Code
 
// Given string
var line = "/*GeeksForGeeks GeeksForGeeks*/";
 
// Function call to check whether then
// given string is a comment or not
isComment(line);
 
     
     

输出：

It is a multi-line comment

时间复杂度： O(N)
辅助空间： O(1)

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