是否可以在 2 个 for 循环中存储数据

Question

我想请用户向我提出 2 或 3 个不同类别的一系列问题。然后我想在 2 或 3 个不同的类别中打印出这些相同的问题。我在 for 循环中使用了 for 循环，但是当我打印时，系统只打印出最新 for 循环中的问题。提前谢谢你。

#include <stdio.h>
#include <stdlib.h>

int main (void)
{
    int tiers;
    char *question [81]; // pointers to binary questions
    int num[81];  // number of binary questions to be asked

    printf("How many tiers do you have? For example if you have high, medium and low categories, you 
    have three tiers.\n");
    scanf("%i", &tiers);

    for (int i = 0; i < tiers; ++i)
    {
        printf("You are in tier number %i\n\n", i+1);
        printf("You will be asked to write a series of binary questions.\n");
        printf("How many questions are you going to ask?\n");
        scanf("%i", &num[i]);
        getchar();

        for (int j =0; j<num[i]; ++j)
        {
            question[j] = malloc(sizeof(char)*584);
            printf("What is question number %i\n", j+1);

            fgets(question[j], 584, stdin);
        }

        printf("\n\n\n");
    }


    /* From here the user is now a different person */
   //asking questions in the respective tiers

    for (int i = 0; i < tiers; ++i)
    {
            printf("You are in tier number %i\n", i+1);
            printf("I am now going to ask you a series of binary questions.\n");
            for ( int j =0; j <num[i]; ++j)
            {
                   printf("\n%s", question[j]);
            }
    }

    for (int i = 0; i < tiers; ++i)
    {
            for (int j =0; j<num[i]; ++j)
            {
                    free (question[j]);
            }
    }

    return 0;
}

Answer 1

您对所有类别使用相同的数组，因此只保存最后一个类别的输入。

您必须使用单独的数组来存储所有输入。

在此代码中，question 是 char* 的 81 个 81 元素数组，而不是原始代码中 char* 的单个 81 元素数组。

#include <stdio.h>
#include <stdlib.h>

int main (void)
{
    int tiers;
    char *question [81][81]; // pointers to binary questions
    int num[81];  // number of binary questions to be asked

    printf("How many tiers do you have? For example if you have high, medium and low categories, you 
    have three tiers.\n");
    scanf("%i", &tiers);

    for (int i = 0; i < tiers; ++i)
    {
        printf("You are in tier number %i\n\n", i+1);
        printf("You will be asked to write a series of binary questions.\n");
        printf("How many questions are you going to ask?\n");
        scanf("%i", &num[i]);
        getchar();

        for (int j =0; j<num[i]; ++j)
        {
            question[i][j] = malloc(sizeof(char)*584);
            printf("What is question number %i\n", j+1);

            fgets(question[i][j], 584, stdin);
        }

        printf("\n\n\n");
    }


    /* From here the user is now a different person */
   //asking questions in the respective tiers

    for (int i = 0; i < tiers; ++i)
    {
            printf("You are in tier number %i\n", i+1);
            printf("I am now going to ask you a series of binary questions.\n");
            for ( int j =0; j <num[i]; ++j)
            {
                   printf("\n%s", question[i][j]);
            }
    }

    for (int i = 0; i < tiers; ++i)
    {
            for (int j =0; j<num[i]; ++j)
            {
                    free (question[i][j]);
            }
    }

    return 0;
}