#include <vector>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <string>
#include <fstream>
#include <stdlib.h>
using namespace std;
•
• //main func declaration etc...
•
//Vectors for storing information from file
vector<string> include;
vector<string> exclude;
string temp; //for storing whatever the stream is on
int len = atoi(puzzle_file >> temp); //first pos
int width = atoi(puzzle_file >> temp); //second pos
The above code is supposed to read in a file and store the numbers in the corresponding ints. I'm getting an error that says "no matching function for call to 'atoi'", even though I have #include <\cstdlib> and #include <\stdlib.h> in my file header. Unsure of where to go from here. Did some research on stackoverflow and other forums, couldn't find anything that really helped me out. Any advice? Thanks
You should use stoi instead of atoi.
stoi takes a std::string as parameter while atoi takes const char* as parameter.
And don't forget stoi is new since c++11.
puzzle_file >> temp expression returns istream, but there is no atoi overload that would accept such a parameter.
You should call atoi(temp.c_str());
You tried to skip one instruction and lost. puzzle_file >> temp returns puzzle_file and not temp. So you apply atoi to an input stream which is converted to a bool. Use:
int len, width;
puzzle_file >> len >> width;
if (! puzzle_file)...
Related
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<<" ";
}
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;
}
I have looked at a few other questions regarding getline() not functioning, however most problems regarding the topic were due to the programmer not including the string header. I have the string header included however getline is still giving me error E0304 (which I have already looked into).
#include <iostream>
#include <string>
#include <sstream>
using namespace std;
int main()
{
char input[100];
getline(cin, input);
cout << input << endl;
}
There are two forms of getline:
std::cin.getline(array, size); // reads into raw character array
getline(std::cin, string); // reads into std::string
You should use a std::string instead of a raw character array:
#include <iostream>
#include <string>
#include <sstream>
int main()
{
std::string input;
getline(std::cin, input);
std::cout << input << "\n";
}
The non-member getline only works with std::string. Use the std::istream member function getline for C-style strings:
std::cin.getline(input, sizeof(input));
I am working with C++ in eclipse CDT and I am trying to convert string to uint64_t by using strtoull but everytime I get below error message -
..\src\HelloTest.cpp:39:42: error: strtoull was not declared in this scope
Below is my C++ example
#include <iostream>
#include <cstring>
#include <string>
using namespace std;
int main() {
string str = "1234567";
uint64_t hashing = strtoull(str, 0, 0);
cout << hashing << endl;
}
return 0;
}
Is there anything wrong I am doing?
Why your solution doesn't work has already been pointed out by others. But there hasn't been a good alternative suggested yet.
Try this for C++03 strtoull usage instead:
#include <string>
#include <cstdlib>
int main()
{
std::string str = "1234";
// Using NULL for second parameter makes the call easier,
// but reduces your chances to recover from error. Check
// the docs for details.
unsigned long long ul = std::strtoull( str.c_str(), NULL, 0 );
}
Or, since C++11, do it directly from std::string via stoull (which is just a wrapper for the above, but saves on one include and one function call in your code):
#include <string>
int main()
{
std::string str = "1234";
// See comment above.
unsigned long long ul = std::stoull( str, nullptr, 0 );
}
Never use char[] or pointers if you have a working alternative. The dark side of C++, they are. Quicker, easier, more seductive. If once you start down the dark path, forever will it dominate your destiny, consume you it will. ;-)
the structure for strtoull is: strtoull(const char *, char * *, int)
You have given it a std::string as pointed out by #juanchopanza
This is the solution I came up with is
#include <iostream>
#include <cstring>
#include <string>
#include <cstdlib>
using namespace std;
int main() {
char str[] = "1234567";
unsigned long long ul;
char* new_pos;
charDoublePointer = 0;
ul = strtoull(str, &new_pos, 0);
cout << ul << endl;
return 0;
}
The output I got was: 1234567
Straight from the eclipse console.
Also at the end of your program you have return 0 out of scope with an extra curly brace.
I'm experimenting with C++ file I/O, specifically fstream. I wrote the following bit of code and as of right now it is telling me that there is no getline member function. I have been told (and insisted still) that there is a member function getline. Anybody know how to use the getline member function for fstream? Or perhaps another way of getting one line at a time from a file? I'm taking in two file arguments on the command line with unique file extensions.
./fileIO foo.code foo.encode
#include <fstream>
#include <iostream>
#include <queue>
#include <iomanip>
#include <map>
#include <string>
#include <cassert>
using namespace std;
int main( int argc, char *argv[] )
{
// convert the C-style command line parameter to a C++-style string,
// so that we can do concatenation on it
assert( argc == 2 );
const string foo = argv[1];
string line;string codeFileName = foo + ".code";
ifstream codeFile( codeFileName.c_str(), ios::in );
if( codeFile.is_open())
{
getline(codeFileName, line);
cout << line << endl;
}
else cout << "Unable to open file" << endl;
return 0;
}
getline(codeFileName, line);
Should be
getline(codeFile, line);
You're passing in the file name, not the stream.
By the way, the getline you're using is a free function, not a member function. In fact, one should avoid the member function getline. It's much harder to use, and harkens back to a day when there was no string in the standard library.
Typo
getline(codeFileName, line);
should be
getline(codeFile, line);
I guess the lesson is you have to learn how to interpret compiler error messages. We all make certain kinds of mistakes and learn the compiler errors they tend to generate.