C++ 字符数组不工作

Question

我试图让这个程序运行，但得到奇怪的输出。我知道 char 缓冲区在这里并不理想，但它是用于分配而不是我自己设计的。这是我的代码:

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


//Place your class definition here
class student {
   public:
      void inputData(int a, char s[20], float e, float m, float sci);
      void printData();

   private:
      int admno;
      char sname[20];
      float eng;
      float math;
      float science;
      float total;
      float ctotal();
};


int main ()   //This is your main driver.  Do NOT make any changes to it
{
    student obj ;
    int a;
    char s[20];
    float e, m, sci;
    cin >> a;
    cin.getline(s,20);
    cin.clear();
    cin.ignore(10,'\n');
    cin >> e;
    cin >> m;
    cin >> sci;
    obj.inputData(a, s, e, m, sci);
    obj.printData();
    return 0;
}

//Place your class member function definitions here

void student::inputData(int a, char s[], float e, float m, float sci) {
   admno = a;
   *sname = *s;
   eng = e;
   math = m;
   science = sci;
   total = ctotal();
}

void student::printData() {
   cout << "Admission number: " << admno << endl << "Student name: ";
   for (int i = 0; i < 20; i++)
      cout << sname[i];
   cout << endl << "English: " << eng << endl << "Math: " << science << endl << "Science: " << science << endl << "Total: " << total;
}

float student::ctotal() {
   return (eng + math + science);
}

这是我的输入:

98745
Kyle Smith
98
78
62

这是预期的输出:

Admission number: 98745
Student name: Kyle Smith
English: 98
Math: 78
Science: 62
Total: 238

这是实际的输出:

Admission number: 98745
Student name:   m  ╩`uÄM■Å■   ║k`u
English: 98
Math: 62
Science: 62
Total: 238

请指教如何修复。我必须坚持使用那个字符缓冲区，但不知道为什么会出现这种损坏。谢谢!

Answer 1

*sname = *s;

这会复制一个字符，而不是整个字符串。如果要复制整个字符串，需要使用std::strcpy

std::strcpy(sname, s);

或循环

char* src = s;
char* dst = sname;
while (src) {
    *dst = *src;
    ++src;
    ++dst;
}

当然，您可以取消所有这些手动字符串处理并使用 std::string相反:

//Place your class definition here
class student {
   public:
      void inputData(int a, std::string s, float e, float m, float sci);
      void printData();

   private:
      int admno;
      std::string sname;
      float eng;
      float math;
      float science;
      float total;
      float ctotal();
};

void student::inputData(int a, std::string s, float e, float m, float sci) {
   admno = a;
   sname = std::move(s);
   eng = e;
   math = m;
   science = sci;
   total = ctotal();
}