I need to make a program in witch I have to read a text from an input file(ifstream fin("input.in")) and store it until the program meets the "#" character. I know it should be doable using fin.getline, but I can't make the "delim" parameter work. I would find useful an explanation of how doe it work, and an example. I already read this, but I couldn't find an example with fin.getline.
This is what I tried, but it doesn't work:
#include <fstream>
#include <string.h>
#include <string>
using namespace std;
ifstream fin("cod.in");
ofstream fout("cod.out");
char chr[100];
for(int i=0;i<n;i++)
{
fin.getline(chr,'#');
fout<<chr<<" ";
}
Related
#include <iostream>
#include <time.h>
#include <string.h>
#include <stdio.h>
int main()
{
string msg;
printf("Enter the message that you wish to display as scroller: ");
getline(cin,msg);
msg=msg+". ";
int x=0;
while(1)
{
Scroll(msg);
wait(100);
system("cls");
x++;
}
cin.get();
return 0;
}
I Have this C code and all strings in the file say 'identifier "string" is undefined'. I tried including <string> instead of <string.h> but it didn't work. Why is it not working?
Add
using namespace std;
After includes (but before main). Or, better, use notion of:
std::string // instead of string
Update: I missed the point of this being C-question. I will leave this answer, but for the sake of formality, use it if you came from Google and you are working with C++.
This is C++ code, not C.
The compiler is probably getting confused because it cannot parse it, so then it finds C-like code and all identifiers do not exist.
The includes should be:
#include <iostream>
#include <ctime>
#include <string>
#include <cstdio>
You are also missing a:
using namespace std;
Plus the definitions for Scroll and wait etc.
I want to open a file named 1.board by calling a function and use getline function to print it's characters to new line.But this is showing a lot of errors.
#include <iostream>
#include <string>
#include <vector>
#include <fstream>
using std::ifstream;
using std::cout;
using std::string;
using std::vector;
void ReadBoardFile(ifstream& search)
{
string line;
search.open("1.board");
while(getline("1.board",line))
{
cout<<line<<"\n";
}
}
int main() {
ifstream fin;
ReadBoardFile(fin);
}
I don't know what i'm doing wrong.I just can't find a perfect and exact answer.
Help,if you can.Thanku!!!!!
So here's your code rewritten so it works.
Two changes, first the first parameter to getline should be the stream you are reading from not the name of a file. I'm guessing that you just weren't concentrating when you wrote that.
Second change, I've moved the stream variable search so that it is local to your ReadBoardFile function. There's no reason in the code you've posted to pass that in as a parameter. You might want to pass the name of the file as a parameter, but I'll leave you to make that change.
void ReadBoardFile()
{
ifstream search("1.board");
string line;
while(getline(search,line))
{
cout<<line<<"\n";
}
}
int main() {
ReadBoardFile();
}
Currently going thru a c++ course.
I had to create a word cipher using the strings: alphabet and key.
to cipher an inputted word with less code as possible I created this solution that gives the error:
no matching function for call to std::basic_string<char>::find(std::string&, int&, int)
I don't know how to solve it, neither do I know if my idea would work at all, would LOVE some help.
Thanks for your attention :)
#include <iostream>
#include <cstring>
#include <string>
using namespace std;
int main() {
string alphabet {"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"};
string key {"XZNLWEBGJHQDYVTKFUOMPCIASRxznlwebgjhqdyvtkfuompciasr"};
string word_to_encrypt {};
getline (cin,word_to_encrypt);
for (int i=0;i<word_to_encrypt.size;i++){
word_to_encrypt.replace (i,1,key,(alphabet.find(word_to_encrypt,i,1)),1);
}
cout<< word_to_encrypt;
}
Two problems:
First size is a function and not a variable. Therefore you need size().
Secondly std::string::find() has no overload which takes a std::string and two ints: https://en.cppreference.com/w/cpp/string/basic_string/find , but you can use the overload which takes a CharT instead by adding .c_str() or .data().
This compiles at least:
#include <iostream>
#include <cstring>
#include <string>
using namespace std;
int main() {
string alphabet {"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"};
string key {"XZNLWEBGJHQDYVTKFUOMPCIASRxznlwebgjhqdyvtkfuompciasr"};
string word_to_encrypt {};
getline (cin,word_to_encrypt);
for (int i=0;i<word_to_encrypt.size();i++){
word_to_encrypt.replace(i, 1, key, (
alphabet.find(word_to_encrypt.c_str(), i, 1)),1);
}
cout<< word_to_encrypt;
}
Check if a string is palindrome
I was using the link above to try to solve this problem (among many others, Ive been trying to solve it various ways all day with no dice, this is my first C++). All other examples are usually in an array format, and I can't make assumptions as to the length of a word.
I'm trying to make a program to detect if a word is a palindrome or not. I have a text file with one word per line, and want to test each word, line by line, if it is a palindrome, and if so to print it to the screen, and if not, to ignore it and not print it.
I figured the best way to locate the palindromes was to reverse the word line by line and match it to the original, and if they are the same (==), then to print it. Here is what I have so far:
#include <iostream>
#include <vector>
#include <string>
#include <cctype>
#include <fstream>
using namespace std;
int main(int argc, char *argv[]) {
std::string line;
std::ifstream infile("wordlist.txt");
}
string reverse(string line){
if (line == string(line.rbegin(), line.rend())) {
cout << string;
}
}
All help is appreciated
I guess your question is a homework question and you would like to get some information on how to complete the C++ coding.
You look not to know how to read file contents in C++.
Here's a link of how to do it:
Read file-contents into a string in C++
I am not very sure about what you specifically would like to be answered. If your question is a homework question, here's some info of how to ask:
https://meta.stackexchange.com/questions/10811/how-do-i-ask-and-answer-homework-questions
#include<iostream>
#include<algorithm>
#include<string.h>
#include<fstream>
using namespace std;
int main() {
string line="", line_rev="";
ifstream infile;
infile.open("wordlist.txt");
do{
infile>>line;
line_rev=line;
reverse(line_rev.begin(), line_rev.end());
if(line==line_rev)
cout<<line<<endl;
}while(getline(infile, line));
//if(infile.is_open()){cout<<"open"<<endl;} //to check if file is open or not
//else{cout<<"unable to open"<<endl;}
return 0;
}
This is the solution. i dont know why you are writing "string reverse(string line)" out side the main() function.
I am experimenting with CGI in C++. I know that there are libraries which handle basic stuff, but in order to know whats going on under the hood i have been trying to parse the stdin using string datatype ---> tokenize using '= and &' then push_back into a vector. at the latter step, i am receiving segmentation fault. given below is the program where i am using cin>> to obtain user input and so on ..
#include <iostream>
#include <stdlib.h>
#include <stdio.h>
#include <vector>
#include <algorithm>
#include <string.h>
using namespace std;
int main()
{
vector <string> stuff(0);
vector<string>::iterator it;
char* bufferchar;
string buffer;
char str[size];
cout<<"Content-type: text/html\n\n"
<<"<html>"
<<"<head>"
<<"<title>CGI SCRIPT</title>"
<<"</head>"
<<"<body>"
fgets(str,20,stdin); //20 is expect size of content from html form
puts(str);
cout<<"<p>Now to break this guy apart";
int x=0;
bufferchar = strtok(str,"&=");
buffer+=bufferchar;
stuff.push_back(buffer);
while(bufferchar!=NULL){
cout<<bufferchar<<'\n'<<'\n';
bufferchar=strtok(NULL,"&=");
buffer+=bufferchar;
stuff.push_back(buffer);
}
cout<<"<br>ok does the vector iterate ?";
for (it=stuff.begin();it!=stuff.end();++it){
cout<<*it;
cout<<"<br> ok man, next <br><br>";
}
cout<<"</body>";
cout<<"</html>";
}