麻煩if if語句C++

Question

我正在研究一個有5個學生的成績簿項目，我想讀取名字，然後用內部循環爲每個學生抓取4個成績。有些東西在這個循環中不起作用。這就是我得到：

請學生1輸入名字：戴夫
請輸入級1號戴夫：100
請輸入級號2戴夫：100
請輸入成績數量3戴夫：100
請輸入級4號戴夫：10
請學生2輸入名字：詹姆斯
請輸入級5號詹姆斯：100
請學生3輸入名稱：山姆
請參閱呃等級5號山姆：100
請學生4輸入名稱：傑克
請輸入級5號傑克：100
請學生5輸入名稱：邁克
請輸入成績數量5 for Mike：100

它應該抓取4個等級，然後才跳到下一個學生。在過去的幾個小時裏，我一直無法弄清楚這一點。下面是代碼我迄今：

#include <iostream> 
#include <string> 

using namespace std; 

const int STUDENTS = 5; //holds how many students we have 
const int SCORES = 4; 

void getNames(string names[], double student1[SCORES], double student2[SCORES], 
      double student3[SCORES], double student4[SCORES], double student5[SCORES],   int SCORES, int STUDENTS); 

int main() 
{ 
    string names[STUDENTS] = {""}; 
    char grades[STUDENTS] = {""}; 
    double student1[SCORES] = {0}; 
    double student2[SCORES] = {0}; 
    double student3[SCORES] = {0}; 
    double student4[SCORES] = {0}; 
    double student5[SCORES] = {0}; 

getNames(names, student1, student2, student3, student4, student5, SCORES, STUDENTS); 


// Make sure we place the end message on a new line 
    cout << endl; 

// The following is system dependent. It will only work on Windows 
    system("PAUSE"); 

    return 0; 
} 

void getNames(string names[], double student1[SCORES], double student2[SCORES], 
      double student3[SCORES], double student4[SCORES], double student5[SCORES],  int SCORES, int STUDENTS) 
{ 
    for (int i = 0; i < STUDENTS; i++) 
    { 
     cout << "Please enter the name for student " << i+1 << ": "; 
     cin >> names[i]; 
     cout << endl; 

     if (i == 0) 
     { 
      int count1 = 0; 
      for (count1; count1 < SCORES; count1++) 
      { 
       cout << "Please enter the grade number " << count1+1 << " for " << names[i] <<": "; 
       cin >> student1[count1]; 
       cout << endl; 
      } 
     } 
     else if (i == 1) 
     { 
      int count2 = 0; 
      for (count2; count2 < SCORES; count2++); 
      { 
       cout << "Please enter the grade number " << count2+1 << " for " << names[i] <<": "; 
       cin >> student2[count2]; 
       cout << endl; 
      } 
     } 
     else if (i == 2) 
     { 
      int count3 = 0; 
      for (count3; count3 < SCORES; count3++); 
      { 
       cout << "Please enter the grade number " << count3+1 << " for " << names[i] <<": "; 
       cin >> student3[count3]; 
       cout << endl; 
      } 
     } 
     else if (i == 3) 
     { 
      int count4 = 0; 
      for (count4; count4 < SCORES; count4++); 
      { 
       cout << "Please enter the grade number " << count4+1 << " for " << names[i] <<": "; 
       cin >> student4[count4]; 
       cout << endl; 
      } 
     } 
     else 
     { 
      int count5 = 0; 
      for (count5; count5 < SCORES; count5++); 
      { 
       cout << "Please enter the grade number " << count5+1 << " for " << names[i] <<": "; 
       cin >> student5[count5]; 
       cout << endl; 
      } 
     } 

    } 
} 

感謝有這方面的幫助！

Answer 1

有一些很粗糙的東西在這裏發生，但問題是，你有除了所有的內部循環分號第一個：

for (count2; count2 < SCORES; count2++); 

刪除分號，大括號中的內容將成爲循環的一部分。

我會建議你讓你的代碼變得更爲簡潔並且不易出錯的夾緊所有這些功能參數到各自爲陣，當你進入的功能，像這樣：

double *scores[5] = { student1, student2, student3, student4, student5 }; 

然後你拿出所有的重複 - 複製/粘貼是什麼原因造成你的問題開始與：

for (int i = 0; i < STUDENTS; i++) 
{ 
    cout << "Please enter the name for student " << i+1 << ": "; 
    cin >> names[i]; 
    cout << endl; 

    for (int s = 0; s < SCORES; s++) 
    { 
     cout << "Please enter the grade number " << s+1 << " for " << names[i] <<": "; 
     cin >> scores[i][s]; 
     cout << endl; 
    } 
} 

Answer 2

你爲什麼不能使用兩個嵌套循環像

for (int studix=0, stduix<STUDENTS; studix++) { 
    //... 
    for (int gradix=0; gradix<SCORE; gradix++) { 
     //... 
    } 
    //.... 
    } 

BTW，條件可能是一個比較複雜的一個，例如與內部環路是

 bool goodgrade=true; 
    for (int gradix=0; goodgrade && gradix<SCORE; gradix++) { 
     // you could modify goodgrade or use break; inside the loop 
    } 

不要忘記一個循環中可能使用的continue和break。

並請，需要時間來閱讀一些優秀的C++編程的書

Answer 3

大廈巴西萊的回答和我的意見：

int main() 
{ 
string names[STUDENTS] = {""}; 
char grades[STUDENTS] = {""}; 
double student1[SCORES] = {0}; 
double student2[SCORES] = {0}; 
double student3[SCORES] = {0}; 
double student4[SCORES] = {0}; 
double student5[SCORES] = {0}; 

double *gradeArray[STUDENTS]; 
gradeArray[0] = student1; 
gradeArray[1] = student2; 
gradeArray[2] = student3; 
gradeArray[3] = student4; 
gradeArray[4] = student5; 

for (int studix=0, stduix<STUDENTS; studix++) { 
// get the name of the student 
for (int gradix=0; gradix<SCORE; gradix++) { 
    // put the grades in gradeArray[studix][gradix]... 

} 
//.... 
} 

是的，我知道大約二維數組，但我想明確地說明如何用「五個單獨的數組」來完成這個工作。笨拙，但我相信這是有效的。