函数的返回值不正确

Question

I'm writing a program that checks an array to see if 3 of the elements in that array are the same value. The program simply outputs "Yes, something is the same 3 times" or "No, nothing repeats 3 times." The program assumes all elements are greater than zero, and that there's only one set that could potentially repeat. For some reason the return value from my function returns either 0 or -2, so the program always defaults to "No, there's no repeating value". We were told to use 3 nested for loops as well.

#include <stdio.h>
#include <stdlib.h>
int same_three(int a[], int n) {
    int i = 0;
    int j = 0;
    int k = 0;
    n = 0;
    int repeated = 0;

    for(i = 0; i < n-2; i++) {
        repeated = a[i];

        for(j = i + 1; j < n-1; j++)
            if(repeated == a[j]) {
                repeated = a[j];
                for(k = j + 1; k < n; k++)
                    if(repeated == a[k]) {
                            return repeated;
                    }
            }
    }
}
int main() {
    int length = 0;
    int i = 0;
    int n = 0;
    int repeated = 0;

    printf("Enter the length of the array: "); //user inputs array length
    scanf("%d", &length);

    int a[length];
    printf("Enter the elements of the array: "); //user inputs individual   elements
    for (i = 0; i < length; i++) {
        scanf("%d", &a[i]);
    }
    repeated = same_three(a, i);
    printf("%d", repeated); //check value for repeated, returning as 0 or negative
    if(repeated > 0){
        printf("There are 3 numbers with the same value in the array: %d", repeated);
    }
    else {
        printf("The array does not contain three numbers with the same value.");
    }
    return 0;
}

Answer 1

There is no return value for if the loop fails to find a repeating value.

At the end of the function you should return the value found or return an error value.

If you wish to follow the single exit principle, then a value should be assigned to the error code at the beginning of the function then changed if a repeated value is found.