继续收到此错误 main.cpp:9:91: error: no match for 'operator<<' （操作数类型是 'std::basic_ostream' 和 'const std::vector'

Question

Sorry in advance if this is lengthy. the problem is within line 9. (where the 2nd cout is.) apparently, but i'm new to this so I can't identify exactly what the issue is.

#include <iostream>
#include <vector>
using namespace std;


void outputRoster(const vector<int> &jersey, const vector<int> &ratings) {
    cout << "ROSTER" << endl;
    for (int i =1; i < jersey.size(); ++i) {
        cout << "Player " << i << " -- Jersey number: " << jersey.at(i-1) << ", Rating: " << ratings << endl;
    }
    cout << endl;
}
void addPlayer(vector<int> &jersey, vector<int> &ratings) {
    int num;
    cout << "Enter another player's jersey number: ";
    cin >> num;
    jersey.push_back(num);
    cout << "Enter another player's ratings: ";
    cin >> num;
    cout << endl;
    ratings.push_back(num);
}
void removePlayer(vector<int> &jersey, vector<int> &ratings) {
    int num;
    cout << "Enter a jersey number: ";
    cin >> num;
    cout << endl;
    for (int i = 0; i < jersey.size(); ++i){
        if (jersey.at(i)==num){
            jersey.erase(jersey.begin()+i);
            ratings.erase(ratings.begin()+i);
            break;
        }
    }
}
void updatePlayerRating(const vector<int> &jersey, vector<int> &ratings){
    int num;
    cout << "Enter a jersey number: " << endl;
    cin >> num;
    for (int i = 0; i < jersey.size(); ++i){
        if(jersey.at(i) == num){
            cout << "Enter a new rating for player: ";
            cin >> num;
            cout << endl;
            ratings.at(i) = num;
        }
    }
}
void outputPlayersAboveRating(const vector<int> &jersey, const vector<int> &ratings) {
    int num;
    cout << "Enter a rating: ";
    cin >> num;
    cout << endl;
    cout << "ABOVE " << num << endl;
    
    for (int i = 0; i < ratings.size(); ++i){
        if (ratings.at(i) > num) {
            cout << "Player " << i+1 << " -- Jersey number: " << jersey.at(i) << ", Rating: " << ratings.at(i);
        }
    }
    cout << endl;
}


int main() {
    vector<int> jersey;
    vector<int> ratings;
    
    for (int i = 0; i < 5; ++i) {
        int num;
        cout << "Enter player " << i+1 << "'s jersey number:";
        cin >> num;
        jersey.push_back(num);
        cout << "Enter player " << i+1 << "'s ratings:";
        cin >> num;
        ratings.push_back(num);
        cout << endl;
        cout << endl;
    }
    
    outputRoster(jersey, ratings);
    
    char inp;
    while(true) {
        cout << "MENU" << endl;
        cout << "a - Add player" << endl;
        cout << "d - Remove player" << endl;
        cout << "u - Update player rating" << endl;
        cout << "r - Output players above a rating" << endl;
        cout << "o - Output roster" << endl;
        cout << "q - Quit" << endl;
        cout << "Choose an option: ";
        
        cin >> inp;
        cout << endl;
        
        if (inp == 'a') {
            addPlayer(jersey, ratings);
        }
        else if (inp == 'd') {
            removePlayer(jersey, ratings);
        }
        else if (inp == 'u') {
            updatePlayerRating(jersey, ratings);
        }
        else if (inp == 'r') {
            outputPlayersAboveRating(jersey, ratings);
        }
        else if (inp == 'o') {
            outputRoster(jersey, ratings);
        }
        else if (inp == 'q') {
            return 0;
        }
    }
    return 0;
}

Any and all help is appreciated also if possible, could you explain how to avoid an error like this in the future. Thanks in advance.

Answer 1

You cannot print ratings directly in cout... << ratings... because std::vector doesn't have an operator overload for printing. Rather, you have to print out an element inside that vector, so change it to cout... << ratings[i]... , which I'm assuming is your desired effect.

This is exactly what the compiler error is telling you. std::vector doesn't have an overload (no operator<< match).