C：迭代for循環，一個ceil語句和odd vs even語句

Question

我是一個相對的初學者與C我寫了我認爲是一個相當簡單的 C程序迭代變量'賽季'內兩-loops。代碼編譯 並運行，但'季節'未被正確跟蹤。我希望有人可能會 願意提供有關如何更正代碼的建議。

下面我提供了我想要的結果，當前C代碼以及代碼爲 的結果。

我想下面的結果：

cohort = 1, class = 1, season = 1 
cohort = 1, class = 2, season = 1 
cohort = 1, class = 3, season = 2 
cohort = 1, class = 4, season = 2 
cohort = 1, class = 5, season = 3 
cohort = 1, class = 6, season = 3 

cohort = 2, class = 1, season = 1 
cohort = 2, class = 2, season = 2 
cohort = 2, class = 3, season = 2 
cohort = 2, class = 4, season = 3 
cohort = 2, class = 5, season = 3 

cohort = 3, class = 1, season = 2 
cohort = 3, class = 2, season = 2 
cohort = 3, class = 3, season = 3 
cohort = 3, class = 4, season = 3 

cohort = 4, class = 1, season = 2 
cohort = 4, class = 2, season = 3 
cohort = 4, class = 3, season = 3 

cohort = 5, class = 1, season = 3 
cohort = 5, class = 2, season = 3 

cohort = 6, class = 1, season = 3 

我的C代碼如下正下方之後，我提出了 結果被返回代碼：

#include <stdio.h> 
#include <math.h> 
char quit; 

main() 
{ 

int mcoht, mclass, season, nmcohts ; 
double season2, cohort2, class2 ; 

nmcohts = 6 ; 

// cohort loop 

for (mcoht=1; mcoht <= nmcohts; mcoht++) { 

    season = ceil(mcoht/2) ; 

    // class loop 

    for (mclass=1; mclass <= (nmcohts-(mcoht-1)); mclass++) { 

    season2 = season ; 
    cohort2 = mcoht ; 
    class2 = mclass ; 

    printf("cohort is: %10.10lf\n", cohort2); 
    printf("class is: %10.10lf\n", class2); 
    printf("season is: %10.10lf\n", season2); 

    // update season (mclass&1) = 0 if mclass even, 1 if mclass is odd 

    if(((mcoht&1) + (mclass&1)) == 1) season = season + 1; 

    } // close class loop 

} // close cohort loop 

    printf("To close type 'quit' and hit the return key\n"); 
    printf("    \n"); 
    scanf("%d", &quit); 

return 0; 

} 

以下是通過返回的結果代碼。除非我犯了一個錯誤 在下面輸入下面的句子，看起來'季節'對於偶數隊列 是正確的，但是對於奇數號 隊列，它看起來像是需要的。

感謝您提出任何有關如何更正代碼或如何改進此帖子的建議 。

cohort = 1, class = 1, season = 0 
cohort = 1, class = 2, season = 0 
cohort = 1, class = 3, season = 1 
cohort = 1, class = 4, season = 1 
cohort = 1, class = 5, season = 2 
cohort = 1, class = 6, season = 2 

cohort = 2, class = 1, season = 1 
cohort = 2, class = 2, season = 2 
cohort = 2, class = 3, season = 2 
cohort = 2, class = 4, season = 3 
cohort = 2, class = 5, season = 3 

cohort = 3, class = 1, season = 1 
cohort = 3, class = 2, season = 1 
cohort = 3, class = 3, season = 2 
cohort = 3, class = 4, season = 2 

cohort = 4, class = 1, season = 2 
cohort = 4, class = 2, season = 3 
cohort = 4, class = 3, season = 3 

cohort = 5, class = 1, season = 2 
cohort = 5, class = 2, season = 2 

cohort = 6, class = 1, season = 3 

我將結果中的代碼示例引號僅作爲列顯示。我不需要如圖所示格式化輸出。我只需要'季節'來正確計算。

Answer 1

我很驚訝這還沒有在半小時內得到答覆......

你與ceil()功能遇到的問題是，你正在使用整數操作數爲師。 C用除了整數運算數的方式進行分割的方式是它會產生一個整數結果，截去任何小數部分。

因此，1/2給出0的結果，而不是0.5。

如果你想要一個浮點結果，你需要強制至少一個操作數爲浮點。因此，而不是：

ceil(mcoht/2) 

嘗試

ceil(mcoht/2.0) 

Answer 2

而且一些事情除了ceil功能：

1. 聲明season2 = season;是多餘的，因爲season已經在內部範圍for循環。
2. 你不需要double s。
3. 按照C99標準，您不應該忽略該函數的返回類型（您的情況爲main）。雖然你可以省略main的參數，你最好把void放在那裏。
4. 在操作員周圍增加一些空間也會有幫助。

Answer 3

您應該完全避免撥打ceil，不需要將事物轉換爲雙倍，進行函數調用並轉換回來。如果我看到這個正確的整數算術(mcoht+1)/2將是完全足夠的。

Answer 4

變量名對我來說沒有任何意義，所以我只是將它們更改爲b和（而不需要c），並在while循環中使用（只是個人偏好）。看起來這個課程的目標是使用mod和/或div來找到模式（第3列是列a +列b div 2）

#include <stdio.h> 

int main(){ 
int a=0, b, num=6; 
while (a++<=num) { b=0; 
    while (b++ <= (num-a)) 
     printf("cohort is: %d class is: %d season is: %d\n", a, b,(a+b)/2); 
} 
return 0; 
}