CODEWITHSUNDEEP
c++stringgetline
user12856563
user12856563

Reputation:

No matching function for call to getline(std::istream&, int&)

I was writing a code which task statements as inputs from user and searches for the word "not" being present in it or not if not is present then it prints Real Fancy else it prints regularly fancy but i am getting an error in such a simple program.

My Code looks like :

#include <iostream>
#include <string.h>
using namespace std;

int main () {
    string str2 (" not ");
    string str3 ("not ");
    string str4 ("not");

    int T;
    std::getline(std::cin, T);
    for (int k=0;k<T;k++){
        string str ;


        std::getline(std::cin, str);
        int len = str.size();
        //condition for only not as a sentence
        if ((str.find(str4) != string::npos) && len ==3) {
            cout<<"Real Fancy";
        }        
        // condition to check for not word in middle of a sentence eg. this is not good
        else if ((str.find(str2) != string::npos) ) {
            cout<<"Real Fancy";
        }        
        // condition if the statement ends with the word not 
        else if (str[len-1]=='t' && str[len-2]== 'o' && str[len-3]== 'n' && str[len-4]== ' '){
            cout<<"Real Fancy";
        }        
        // code to check for if statement starts with word not
        else if ((str.find(str3) != string::npos) ) {
            cout<<"Real Fancy";
        }
        else {
            cout<<"regularly fancy";
        }
        cout<<endl;
    }
    return 0;
}

and the error i am getting once i run this code is :

main.cpp:11:30: error: no matching function for call to ‘getline(std::istream&, int&)’

Upvotes: 3

Views: 13850

Answers (4)

NutCracker
NutCracker

Reputation: 12283

std::getline has the following overloads:

istream& getline (istream&  is, string& str, char delim);
istream& getline (istream&& is, string& str, char delim);
istream& getline (istream&  is, string& str);
istream& getline (istream&& is, string& str);

and, as you can see, none of them receives integer as a second parameter, so here are possible solutions for you:

  • if you are limited to C++11, use std::stoi in a following manner:
std::string line;
std::getline(std::cin, line);
int T = std::stoi(line);
  • if you are able to use C++17, I would strongly recommend you to use std::from_chars as follows:
int value = 0;
std::string line;
std::getline(std::cin, line);
const auto result = std::from_chars(str.data(), str.data() + str.size(), value);
if (result.ec == std::errc()) {
    // strings is successfully parsed
}

Why is std::from_chars better than std::stoi?

Because std::from_chars is non-throwing and gives you better error reporting (which will give you more info about the conversion outcome). Also, it is a bit faster than std::stoi according to some resources. Read more about std::from_chars here.

Upvotes: 1

Jan Schultke
Jan Schultke

Reputation: 39959

std::getline has two overloads:

(1) istream& getline (istream& is, string& str, char delim);
(2) istream& getline (istream& is, string& str);

You are trying to call it with an int parameter, which won't work.

There are two ways to solve this:

Use std::stoi to parse the int after reading into a std::string

Read from the stream directly into an int by using std::cin >> T. This will not consider new lines specially though and use any whitespace as a separator between ints. So if you are trying to parse exactly one int per line, the former option will suit your better.

Upvotes: 2

csguy
csguy

Reputation: 1484

According to http://www.cplusplus.com/reference/string/string/getline/

You should be looking to use getline in this form:

istream& getline (istream&  is, string& str); 
istream& getline (istream&& is, string& str);

You do this:

int T;
std::getline(std::cin, T);

T is an integer and there is no such call that can be made.

Upvotes: 0

Lukas
Lukas

Reputation: 64

std::getline() function is not for integer type. If you want to use std::getline() for your integer, you should declare temporary string type value. for example in your case

int T;
std::string tmp_s;
std::getline(std::cin, tmp_s);
T = std::stoi(tmp_s);

Upvotes: 2

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