c - 检测数组中的数是否已经输入(C程序)

Question

我有点迷茫。我想编写一个程序，如果数组中的数字已经输入，那么它会检测到它并说它重复了，所以程序会告诉用户输入另一个非重复的整数。

#include <stdio.h>
#define SIZE 5

int main()
{
    int array[SIZE];
    int i;
    int j;


    for (i = 0; i < SIZE; i++)
    {
        printf("[%d] Insert a number: ", i + 1);
        scanf("%d", &array[i]);

        j = i - 1; // This is the closest that I've gotten guys. But I need to create a loop to make j be -1 until it finds a repeated number in the array.

        if (array[i] == array[j])
        {
            printf("The number is repeated");
            i--;
        }

        if (array[i] > 1000)
        {
            printf("Sorry, the number you entered cannot be bigger than 1000\n");
            i--;
        }

        if (array[i] < 0)
        {
            printf("Sorry, the number you entered cannot be less than 0\n");
            i--;
        }
    }

    for (i = 0; i < SIZE; i++)
    {
        printf("The array inside is %d\n", array[i]);
    }


    return 0;
}

如您所见，我做了类似的事情。我只是把 j = i - 1 所以基本上它会告诉程序它被重复了。但是，我想我应该创建一个循环，将 -1 减去 j 直到它找到重复值(如果有的话)。我只是不知道如何创建该循环并使其工作。

非常感谢!

Answer 1

可以通过以下方式进行检查(无需测试)

int array[SIZE];
int i;


for (i = 0; i < SIZE; i++)
{
    int valid = 1;
    int num;

    do
    {

        printf("[%d] Insert a number: ", i + 1);
        scanf("%d", &num );

        if ( !( valid = !( num > 1000 ) ) )
        {
            printf("Sorry, the number you entered cannot be bigger than 1000\n");
        }
        else if ( !( valid = !( num < 0 ) ) )
        {
            printf("Sorry, the number you entered cannot be less than 0\n");
        }
        else
        {
            int j = 0;
            while ( j < i && num != array[j] ) j++;

            if ( !( valid = j == i ) )
            {
                printf("The number is repeated");
            }
        }
    } while ( !valid );

    array[i] = num;
}