C將數字列表讀入多個數組

Question

所以我想編寫一個程序，提示用戶輸入用戶希望擁有多少數據集，也就是將有多少個數組。然後它會提示用戶輸入每個數據集中有多少個值以及這些值是多少。最後，它爲用戶提供了在所需數據集上運行的選項列表。

當我運行我的代碼並選擇要使用的數據集時，它似乎總是拿出最後一個數據集並且似乎沒有集合中的所有值。我只是想知道，如果有人能讓我知道我做錯了什麼，或者至少讓我走上正軌。我已經多次閱讀代碼並且無法弄清楚。

#include <stdio.h> 

int main() 
{ 
    unsigned short int num_sets, set_size, set_desired, command = 0; 
    printf("Enter the number of data sets you would like to store: "); 
    scanf(" %hu", &num_sets); 

    int i = 1, j, sets[1][num_sets], sum, a; 

    while(i <= num_sets) 
    { 
     j = 1; 
     printf("Enter the number of elements in data set %hu: ", i); 
     scanf(" %hu", &set_size); 
     printf("Enter the data for set %hu: ", i); 
     while(j < set_size) 
     { 
      scanf(" %d", &sets[i - 1][j - 1]); 
      j++; 
     } 
     i++; 
    } 

    printf("Which set would you like to use?: "); 
    scanf(" %hu", &set_desired); 
    while(set_desired > num_sets){ 
     printf("There aren't that many data sets, try again: "); 
     scanf(" %hu", &set_desired); 
    } 
    printf("Set #%hu: %hu\n", num_sets, *sets[num_sets - 1]); 

    while(command != 7){ 
     printf("Choose what you would like to do:\n"); 
     printf("1. Find the minimum value.\n"); 
     printf("2. Find the maximum value.\n"); 
     printf("3. Calculate the sum of all the values.\n"); 
     printf("4. Calculate the average of all the values.\n"); 
     printf("5. Sort the values in ascending order.\n"); 
     printf("6. Select a different data set.\n"); 
     printf("7. Exit the program.\n"); 
     scanf(" %hu", &command); 
     if(command == 1){ 
      printf("You picked 1!"); 
     } 
     if(command == 2){ 
      printf("You picked 2!"); 
     } 
     if(command == 3){ 
      /*printf("You picked 3!"); 
      for(a = 0; a < set_size; a++){ 
       sum = sum + *sets[a]; 
      } 
      printf("%d\n", sum);*/ 
      printf("You picked 3!"); 
     } 
     if(command == 4){ 
      printf("You picked 4!"); 
     } 
     if(command == 5){ 
      printf("You picked 5!"); 
     } 
     if(command == 6){ 
      printf("You picked 6!"); 
     } 
     if(command == 7){ 
      break; 
     } 
    } 
} 

Answer 1

If you are trying to store values in different sets than you need to maintain the number of items in each set separately as you don't know how many elements are there is each set. 

The design should be such that: 
Set 1 : Number of Elements : Actual values in the array.(Here I am storing the number of items in the set as part of the same array. It will be the first element in each set) 

The memory allocation can be done dynamically as you are giving the option to the user to set the number of items per set. 

#include <stdio.h> 
#include<stdlib.h> 
int main() 
{ 
    unsigned short int num_sets, set_size, set_desired, command = 0; 
    printf("Enter the number of data sets you would like to store: \n"); 
    scanf(" %hu", &num_sets); 

    int *sets[num_sets]; 
    int i = 0, k=0,j,sum, a; 

    while(i < num_sets) 
    { 
     j = 1; 
     printf("Enter the number of elements in data set %hu: \n", i+1); 
     scanf(" %hu", &set_size); 
     sets[i] = (int *) malloc((sizeof(int)*set_size)); 
     *sets[i] = set_size; 
     printf("Enter the values for set %hu\n", i+1); 
     while(j <= set_size) 
     { 
     scanf(" %d", &sets[i][j]); 
     j++; 
     } 
     i++; 
    } 
    printf("Which set would you like to use?: \n"); 
    scanf(" %hu", &set_desired); 
    while(set_desired > num_sets){ 
     printf("There aren't that many data sets, try again: \n"); 
     scanf(" %hu", &set_desired); 
    } 
    for(k=1;k<=(*sets[set_desired-1]);k++) 
    { 
     printf("Set #%hu: %hu \n", set_desired, *(sets[set_desired-1] + k)); 
    } 

    while(command != 7){ 
     printf("Choose what you would like to do:\n"); 
     printf("1. Find the minimum value.\n"); 
     printf("2. Find the maximum value.\n"); 
     printf("3. Calculate the sum of all the values.\n"); 
     printf("4. Calculate the average of all the values.\n"); 
     printf("5. Sort the values in ascending order.\n"); 
     printf("6. Select a different data set.\n"); 
     printf("7. Exit the program.\n"); 
     scanf(" %hu", &command); 
     if(command == 1){ 
     printf("You picked 1!"); 
     } 
     if(command == 2){ 
     printf("You picked 2!"); 
     } 
     if(command == 3){ 
     /*printf("You picked 3!"); 
      *    for(a = 0; a < set_size; a++){ 
      *        sum = sum + *sets[a]; 
      *           } 
      *              printf("%d\n", sum);*/ 
     printf("You picked 3!"); 
     } 
     if(command == 4){ 
     printf("You picked 4!"); 
     } 
     if(command == 5){ 
     printf("You picked 5!"); 
     } 
     if(command == 6){ 
     printf("You picked 6!"); 
     } 
     if(command == 7){ 
     break; 
     } 
    } 
    return 0; 
}                                                

Answer 2

您的代碼中存在未定義的行爲。在這一行：

int i = 1, j, sets[1][num_sets], sum, a; 

您每num_sets組數據中的一個要素分配足夠的空間。這不是你真正需要的。您可能需要將num_sets作爲第一個索引，並且您需要爲其他索引創建更大的值。

您可能需要執行動態內存分配。否則，你需要設置數組大小的上限（可能是100），並拒絕嘗試創建更大的數組。然後，您將使用：

enum { MAX_ARR_SIZE = 100 }; 

int sets[num_sets][MAX_ARR_SIZE]; 

爲變量。你的數據錄入循環已經採用了這種索引方法。您可能需要記錄每行中有多少條記錄，以避免使用未初始化的數據。

int set_size[num_sets];