如何停止讀取輸入並分析數據C

Question

我需要在C中創建一個代碼，它讀取一系列數字，第一個數字是產品編號（介於1和產品總數之間）通過輸入），第二個數字是1-10的評分，並將其存儲在二維數組中。從1開始的數組行是產品編號，1-10列是評級。第11列是星星的總數，第12列是總分數。我必須使用scanf來讀取值，並且當scan（）！= 2時，循環應停止並生成報告。

報告應列出每種產品的評分數量（即2個評分爲5星，17個評分爲10星等）以及平均評分。

我想我的邏輯是正確的，我的代碼編譯了，但是當我嘗試生成一個報告時，它一直返回錯誤。任何線索的問題可能是什麼？

這是我到目前爲止的代碼：你從標準輸入一排，我要做到不認爲兩次讀取

int productStar[][13] = {0}; 
int i = 0; 
int product = 0; 
int stars = 0; 
int howMany = 0; 
int ratings = 0; 
float avg = 0; 
int sum = 0; 

printf("How many unique products?\n"); 
scanf("%d", &howMany); 

printf("Please enter product # and stars\n"); 

while(1) 
{ 
    scanf("%d %d", &product, &stars); /* Reads in two values; first is product number, second is rating */ 

    if (scanf("%d %d", &product, &stars) != 2) /* kills the loop */ 
    { 
     printf("Hi from the inside\n"); 
     break; 
    } 


    productStar[product][stars] += 1; /* adds tally to specific product rating */ 

    productStar[product][11] += stars; /* increments total number of stars; used later to find avg */ 

    productStar[product][12] += 1; /* increments how many ratings */ 

} 

for (int product = 0; product <= howMany; ++product) 
{ 
for (int stars = 0; stars <= 10; ++stars) 
    { 
     avg = productStar[product][11]/productStar[product][12]; 

     printf("Product %d Information:\n", product); 
     printf("1 star: %d\n", productStar[product][1]); 
     printf("2 star: %d\n", productStar[product][2]); 
     printf("3 star: %d\n", productStar[product][3]); 
     printf("4 star: %d\n", productStar[product][4]); 
     printf("5 star: %d\n", productStar[product][5]); 
     printf("6 star: %d\n", productStar[product][6]); 
     printf("7 star: %d\n", productStar[product][7]); 
     printf("8 star: %d\n", productStar[product][8]); 
     printf("9 star: %d\n", productStar[product][9]); 
     printf("10 star: %d\n", productStar[product][10]); 
     printf("Average rating: %2.2f out of 10 (%d ratings total).\n", avg, ratings); 
     printf("--------------------\n"); 
    } 
} 

for (product = 0; product <= howMany; ++product) 
{ 
    sum += productStar[product][12]; 
    /* Sum of all ratings */ 
} 

printf("%d product ratings evaluated in all.\n\n", sum); 


return 0; 

}

Answer 1

。也許嘗試改變第二scanf裏面的你輸入讀循環來檢查，看看是否產品與明星不爲空字符串聲明：

while(1) { 
     scanf("%d %d", &product, &stars); /* Reads in two values; first is product number, second is rating */ 

     if (product == '\0' || stars == '\0') /* kills the loop */ 
     { 
      // Break out of input loop and process data. 
      break; 
     } 
    } 

    // Processing code. 

此外，這是一個好主意，用零來檢查師：

if (productStar[product][12] != 0) { 
    avg = productStar[product][11]/productStar[product][12]; 
} 

後，我做了這些改變你的代碼的工作完美:)

#include <stdio.h> 

int productStar[][13] = {0}; 
int i = 0; 
int product = 0; 
int stars = 0; 
int howMany = 0; 
int ratings = 0; 
float avg = 0; 
int sum = 0; 

int main(void) { 
    printf("How many unique products?\n"); 
    scanf("%d", &howMany); 

    printf("Please enter product # and stars\n"); 

    while(1) 
    { 


     scanf("%d %d", &product, &stars); /* Reads in two values; first is product number, second is rating */ 

     if (product == '\0' || stars == '\0') /* kills the loop */ 
     { 
      break; 
     } 


     productStar[product][stars] += 1; /* adds tally to specific product rating */ 

     productStar[product][11] += stars; /* increments total number of stars; used later to find avg */ 

     productStar[product][12] += 1; /* increments how many ratings */ 

    } 

    for (int product = 0; product <= howMany; ++product) 
    { 
    for (int stars = 0; stars <= 10; ++stars) 
     { 
     if (productStar[product][12] != 0) { 
      avg = productStar[product][11]/productStar[product][12]; 
     } 

      printf("Product %d Information:\n", product); 
      printf("1 star: %d\n", productStar[product][1]); 
      printf("2 star: %d\n", productStar[product][2]); 
      printf("3 star: %d\n", productStar[product][3]); 
      printf("4 star: %d\n", productStar[product][4]); 
      printf("5 star: %d\n", productStar[product][5]); 
      printf("6 star: %d\n", productStar[product][6]); 
      printf("7 star: %d\n", productStar[product][7]); 
      printf("8 star: %d\n", productStar[product][8]); 
      printf("9 star: %d\n", productStar[product][9]); 
      printf("10 star: %d\n", productStar[product][10]); 
      printf("Average rating: %2.2f out of 10 (%d ratings total).\n", avg, ratings); 
      printf("--------------------\n"); 
     } 
    } 



    for (product = 0; product <= howMany; ++product) 
    { 
     sum += productStar[product][12]; 
     /* Sum of all ratings */ 
    } 

    printf("%d product ratings evaluated in all.\n\n", sum); 


    return 0; 
}