I am trying to find the duplicate of elements in an array - arrays

Question

Can someone help me to figure out why my code is unable to accurately find the duplicate of elements?
#include <stdio.h>
int main() {
int array[10];
int count = 0;
printf("Enter a maximum of 10 values to store in an array: ");
for (int i = 0; i < 10; i++) {
scanf_s("%d", &array[i]);
}
for (int i = 0; i < 10; i++) {
for (int j = i + 1; j < 10; j++) {
if (array[i] == array[j]) {
count++;
break;
}
}
}
printf("The duplicates are : %d ", count);
}
I'm a beginner at this language so any advice and suggestions to help me solve this exercise will be much appreciated.

Answer 1

First of all the first loop runs 10 times even if the user enters less numbers. You can fix that by doing:
for (int i = 0; scanf_s("%d", &array[i]) == 1 && i < 10; i++);
Then the logic of the other two loops is wrong. I initially got wrong what you meant. I thought you wanted to know how many times a number is duplicated. So I wrote the wrong program and then modified it for your purposes. Here is your program:
#include <stdio.h>
int main() {
int n[10];
int dupes[5], d = 0;
int flag = 1, omg;
for ( omg = 0; scanf("%d", &n[omg]) == 1 && omg < 10; omg++);
for (int i = 0; i < omg; i++) {
for (int j = i+1; j < 10; j++) {
if( n[i] == n[j] ) {
if( d > 0 ) {
for(int k = 0; k < d; k++) {
if( n[i] == dupes[k] ) {
flag = 0;
break;
}
}
}
if( flag ) {
dupes[d] = n[i];
++d;
break;
}
else {
flag = 1;
break;
}
} // end outer if
}
}
printf("There are %d numbers that have at least one dupe\n", d);
return 0;
}
I named a variable omg out of desperation, writing this program was a nightmare. (Because it came from the ashes of a previous program)

Answer 2

Your code correctly determines the number of duplicate entries in the array.
If instead you want to determine the number of duplicated values, you must modify the algorithm:
#include <stdio.h>
int main() {
int array[10] = { 0 };
int count = 0;
printf("Enter a maximum of 10 values to store in an array: ");
for (int i = 0; i < 10; i++) {
scanf_s("%d", &array[i]);
}
for (int i = 0; i < 10; i++) {
for (int j = 0; j < 10; j++) {
if (array[i] == array[j]) {
if (i < j)
count++;
if (i != j)
break;
}
}
}
printf("There are %d duplicate values\n", count);
return 0;
}

Answer 3

I use a structure 'Number' which contains the number and its duplicate, then I fill the array and I put it in ascending order then I calculate the number of duplicate of each number and I fill in the strecture like this :
my code:
#include <stdio.h>
#define size 10
typedef struct Number
{
int number;
int duplicate;
}Number;
int main()
{
int array[size];
Number array2[size];
int count = 0;
printf("Enter a maximum of 10 values to store in an array: ");
for (int i = 0; i < size; i++)
{
scanf("%d", &array[i]);
}
int temp=size;
int temppppp=0;
for(int i=0;i<size;i++)
{
for(int j=i+1;j<size;j++)
{
if(array[i]>array[j])
{
temppppp=array[i];
array[i]=array[j];
array[j]=temppppp;
}
}
}
printf("\n\n");
for (int i = 0; i < size; i++)
{
printf("[%d]",array[i]);
}
printf("\n\n");
int i=0;
int j=0;
while(i<size)
{count=1;
while(i<(size-1)&&array[i]==array[i+1])
{
count++;
i++;
}
if(count>=2)
{
array2[j].number=array[i-1];
array2[j].duplicate=count;
j++;
}
i++;
}
int p=0;
while(p<j)
{
printf("\n[%d] has duplicated %d times !\n",array2[p].number,array2[p].duplicate);
p=p+1;
}
printf("\n\n");
printf("\nThere are %d duplicate values\n", j);
}