C for回圈在輸入后結束

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

struct Student {
    string name;
    string hometown;
    int age;
    int games;
    int* hours = new int [games];
};

int main(){
    int players;
    Student* s = new Student [players];

    cout << "How many esports players are there at TTU who major in csc?\n";
    cin >> players;
    cout << "\nPlease enter in information about each player: \n\n";

    for(int i = 0; i < players; i  ){
        cout << "PLAYER " << (i   1) << ":\n";
        cout << "\tNAME:\t";
        getline(cin >> ws, s[i].name);
        cout << "\tHOMETOWN:\t";
        getline(cin >> ws, s[i].hometown);
        cout << "\tAGE:\t";
        cin >> s[i].age;
        cout << "\tHOW MANY GAMES DOES " << s[i].name << " PLAY?\t";
        cin >> s[i].games;
            for(int j = 0; j < s[i].games; j  ){
                cout << "NUMBER OF HOURS " << s[i].name << "PLAYED GAME"  << (j   1) << "\t";
                cin >> s[i].hours[j];
            }
    } 

    return 0;
}

出于某種原因，for 回圈在詢問年齡后結束。我試過多個輸入，它做同樣的事情。我是 C 的新手。有誰知道為什么？感謝您的時間

uj5u.com熱心網友回復：

您沒有正確處理陣列。您正在使用未初始化的變數為其大小分配它們：

• in int games; int* hours = new int [games];，games未初始化。
• in int players; Student* s = new Student [players];，players未初始化。

而且，即使您正確分配了陣列，您也會泄漏它們，因為在使用完它們后您并沒有釋放它們。

當您需要使用直到運行時才知道其大小的陣列時，您可以正確使用new[]，但在您確定大小之后才能使用，例如：

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

struct Student {
    string name;
    string hometown;
    int age = 0;
    int games = 0;
    int* hours = nullptr;
};

int main(){
    cout << "How many esports players are there at TTU who major in csc?\n";

    int players;
    cin >> players;

    Student *s = new Student[players];

    cout << "\nPlease enter in information about each player: \n\n";

    for(int i = 0; i < players;   i){
        cout << "PLAYER " << (i   1) << ":\n";
        cout << "\tNAME:\t";
        getline(cin >> ws, s[i].name);
        cout << "\tHOMETOWN:\t";
        getline(cin >> ws, s[i].hometown);
        cout << "\tAGE:\t";
        cin >> s[i].age;
        cout << "\tHOW MANY GAMES DOES " << s[i].name << " PLAY?\t";
        cin >> s[i].games;
        s[i].hours = new int[s[i].games];
        for(int j = 0; j < s[i].games;   j){
            cout << "NUMBER OF HOURS " << s[i].name << " PLAYED GAME " << (j   1) << "\t";
            cin >> s[i].hours[j];
        }
    }

   // use player info as neded...

    for(int i = 0; i < players;   i){
        delete[] s[i].hours;
    }
    delete[] s;

    return 0;
}

話雖如此，您應該手動使用/std::vector代替，例如：new[]delete[]

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

struct Student {
    string name;
    string hometown;
    int age = 0;
    int games = 0;
    std::vector<int> hours;
};

int main(){
    cout << "How many esports players are there at TTU who major in csc?\n";

    int players;
    cin >> players;

    std::vector<Student> s(players);

    cout << "\nPlease enter in information about each player: \n\n";

    for(int i = 0; i < players;   i){
        cout << "PLAYER " << (i   1) << ":\n";
        cout << "\tNAME:\t";
        getline(cin >> ws, s[i].name);
        cout << "\tHOMETOWN:\t";
        getline(cin >> ws, s[i].hometown);
        cout << "\tAGE:\t";
        cin >> s[i].age;
        cout << "\tHOW MANY GAMES DOES " << s[i].name << " PLAY?\t";
        cin >> s[i].games;
        s[i].hours.resize(s[i].games);
        for(int j = 0; j < s[i].games;   j){
            cout << "NUMBER OF HOURS " << s[i].name << " PLAYED GAME " << (j   1) << "\t";
            cin >> s[i].hours[j];
        }
    } 

    // use player info as needed...

    return 0;
}

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