不包括最後一個項目之後逗號在打印清單

Question

我有印號碼列表：

1：1，
2：1，2，
3：1,3 ，

如何在每行上不包含最後一個逗號？檢查

for (int i = 1; i <= x; ++i) 
    { 
    cout << i << ": "; 
    for (int j = 1; j <= i; ++j) 
    { 
     if (i % j == 0) 
     { 
     cout << j << ", "; 
     } 
    } 
    cout << endl; 
    } 

Answer 1

試試這個：

for (int i = 1; i <= x; ++i) 
{ 
cout << i << ": "; 
for (int j = 1; j <= i; ++j) 
{ 
    if (i==j) { 
     cout << j;  
    } else if (i % j == 0) { 
     cout << j << ", "; 
    } 
} 
cout << endl; 
} 

Answer 2

嘗試，如果數字是最後不便，如：

for (int i = 1; i <= x; i++) 
{ 
    cout << i << ": "; 
    for (int j = 1; j <= i; j++) 
     if (!(i % j)) 
     { 
      if (j != i) 
       cout << j << ", "; 
      else 
       cout << j << endl; 
     } 
} 

Answer 3

for (int i = 1; i <= x; ++i) 
{ 
    cout << i << ": "; 
    for (int j = 1; j <= i; ++j) 
    { 
     if (i % j == 0) 
     { 
      cout << j; 
      if (i != j) { 
       cout << ", "; 
      } 
     } 
    } 
    cout << endl; 
} 

Answer 4

因爲你總是輸出1，開始在2

檢查

for (int i = 1; i <= x; ++i) 
{ 
    cout << i << ": 1"; 
    for (int j = 2; j <= i; ++j) 
    { 
     if (i % j == 0) 
     { 
      cout << ", " << j; 
     } 
    } 
    cout << endl; 
} 

或者，您可以用隔板

for (int i = 1; i <= x; ++i) 
{ 
    char sep = ':' 
    cout << i; 
    for (int j = 1; j <= i; ++j) 
    { 
     if (i % j == 0) 
     { 
      cout << sep << " " << j; 
      sep = ','; 
     } 
    } 
    cout << endl; 
}