"Ambiguous Overload" issues in loop, and malfunctioning cin - c++

Question

I'm building a menu creation class with a member function that should display the menu, get a selection from the user, test if it's a valid menu item, and return the number of the item. For some reason, the compiler is giving me an "ambiguous overload for operator '>>'" error on a simple cin statement in the run() member function below. When run, the function catches invalid input properly, but then considers all input after that invalid. If the first input is correct, the program terminates outright. Here's my code:
#include <iostream>
#include <vector>
using namespace std;
class NumericalMenu {
private:
string prompt;
vector<string> options;
string canceltext;
string errortext;
bool repeatprompt;
int sel;
public:
NumericalMenu() {
prompt = "Choose an option:";
canceltext = "Cancel";
errortext = "Error!";
repeatprompt = true;
sel = 0;
};
void setPrompt(string text) {
prompt = text;
};
int size() const {
int size = options.size() + 1;
return size;
};
int addOption(string text) {
options.push_back(text);
int position = options.size() - 1;
return position;
};
void setCancelText(string text) {
canceltext = text;
};
void setRepeatPromptOnError(bool repeat) {
repeatprompt = repeat;
};
void setErrorText(string text) {
errortext = text;
};
int run() const{
cout << prompt << "\n\n";
for (unsigned i=0; i<options.size(); i++) {
cout << i+1 << " - " << options[i] << "\n";
}
int errorpos = this->size();
cout << errorpos << " - " << canceltext << "\n\n";
cin.clear();
cin.ignore();
cin >> sel;
if(cin.fail() || sel<=0 || sel>errorpos) {
cout << "\n" << errortext << "\n\n";
if(repeatprompt == true) {
cin.clear();
cin.ignore();
this->run();
}
}
if (sel == errorpos) {
return -1;
} else {
return sel;
}
};
};
int main() {
NumericalMenu menu;
menu.setPrompt("Choose an option:");
menu.addOption("Enter new values");
menu.addOption("Help");
menu.addOption("Save");
menu.setCancelText("Exit");
menu.run();
}
Edit: Got it! Thanks everyone. The working header:
#include <iostream>
#include <vector>
#include <string>
using namespace std;
class NumericalMenu {
private:
string prompt;
vector<string> options;
string canceltext;
string errortext;
bool repeatprompt;
public:
NumericalMenu() {
prompt = "Choose an option:";
canceltext = "Cancel";
errortext = "Error!";
repeatprompt = true;
};
void setPrompt(string text) {
prompt = text;
};
int size() const{
int size = options.size() + 1;
return size;
};
int addOption(string text) {
options.push_back(text);
int position = options.size() - 1;
return position;
};
void setCancelText(string text) {
canceltext = text;
};
void setRepeatPromptOnError(bool repeat) {
repeatprompt = repeat;
};
void setErrorText(string text) {
errortext = text;
};
int run() const{
cout << prompt << "\n\n";
for (unsigned i=0; i<options.size(); i++) {
cout << i+1 << " - " << options[i] << "\n";
}
int errorpos = this->size();
cout << errorpos << " - " << canceltext << "\n\n";
int sel;
cin.clear();
cin >> sel;
if(cin.fail() || sel<=0 || sel>errorpos) {
cout << "\n" << errortext << "\n\n";
if(repeatprompt == true) {
cin.clear();
cin.ignore(1000, '\n');
int sele = this->run();
return sele;
}
}
if (sel == this->size()) {
return -1;
}
else {
return sel;
}
};
};

Answer 1

You declared your run() function as const and preventing modifications to member variables is being enforced by the compiler.
class NumericalMenu {
private:
int sel;
...
int run() const {
cin >> sel; // Not allowed
If you need to modify member variables, remove the const in your inline run() function definition.
Furthermore as a good practice try to include all the headers you directly use in your code (i.e. <string>).