Remove comments from a given C/C++ program
Given a C/C++ program, remove comments from it.
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The idea is to maintain two flag variables, one to indicate that a single line comment is started, another to indicate that a multiline comment is started. When a flag is set, we look for the end of comment and ignore all characters between start and end.
Following is C++ implementation of above idea.
C
// C++ program to remove comments from a C/C++ program#include <iostream>using namespace std;string removeComments(string prgm){ int n = prgm.length(); string res; // Flags to indicate that single line and multiple line comments // have started or not. bool s_cmt = false; bool m_cmt = false; // Traverse the given program for (int i=0; i<n; i++) { // If single line comment flag is on, then check for end of it if (s_cmt == true && prgm[i] == '\n') s_cmt = false; // If multiple line comment is on, then check for end of it else if (m_cmt == true && prgm[i] == '*' && prgm[i+1] == '/') m_cmt = false, i++; // If this character is in a comment, ignore it else if (s_cmt || m_cmt) continue; // Check for beginning of comments and set the appropriate flags else if (prgm[i] == '/' && prgm[i+1] == '/') s_cmt = true, i++; else if (prgm[i] == '/' && prgm[i+1] == '*') m_cmt = true, i++; // If current character is a non-comment character, append it to res else res += prgm[i]; } return res;}// Driver program to test above functionsint main(){ string prgm = " /* Test program */ \n" " int main() \n" " { \n" " // variable declaration \n" " int a, b, c; \n" " /* This is a test \n" " multiline \n" " comment for \n" " testing */ \n" " a = b + c; \n" " } \n"; cout << "Given Program \n"; cout << prgm << endl; cout << " Modified Program "; cout << removeComments(prgm); return 0;} |
Output
Given Program
/* Test program */
int main()
{
// variable declaration
int a, b, c;
/* This is a test
multiline
comment for
testing */
a = b + c;
}
Modified Program
int main()
{
int a, b, c;
a = b + c;
}This article is contributed by Sachin Gupta. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above
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