Thread: Program to find repeated number in array

Logic to find repeated number in array

compare array element

array[0] == array[1]
array[0] == array[2]
array[0] == array[3]
array[0] == array[4]


array[1] == array[0]
array[1] == array[2]
array[1] == array[3]
array[1] == array[4]


array[2] == array[0]
array[2] == array[1]
array[2] == array[3]
array[2] == array[4]


array[3] == array[0]
array[3] == array[1]
array[3] == array[2]
array[3] == array[4]


array[4] == array[0]
array[4] == array[1]
array[4] == array[2]
array[4] == array[3]

Code:

#include <stdio.h>


int main ()
{
    int i, array[5] = {1, 2, 3, 4, 4};
    
    int duplicate = array[0];


     for ( i = 1; i <5; i++)
         
         { 
           if (duplicate ==array[i]
           {
               printf("%d ", duplicate);
           }
         }
            
    return 0;
}

How to check all conditions

Originally Posted by Salem

Perhaps make your code follow your logic, which suggests you need two nested loops.

I'm trying to implement logic. I understand nested loops.

Code:

#include <stdio.h>

int main(void)
 {
        
        int i, j;
        
        for( i = 0; i < 5; i++)
        {
           printf(" i = %d \n", i);
        
                  for( j = 0; j < 5; j++)
                       {
                             printf(" j = %d \n",j);  
                        }           
           
        }
        
        return 0;
}

Originally Posted by Salem

> What's wrong here
Did you do as I suggested, or did you lunge straight for the problem without understanding intermediate steps?

When I run that program it find repeated number but it print that number five times like 44444

I just want to find repeat number and that is 4

Originally Posted by Salem

So what happened to the "int duplicate = array[0];" idea, except you now make it int duplicate = array[i];

This program find repeated number

Code:

#include <stdio.h> 

int main(void)
 {
         
        int i, j;
		
        int array[5] = {1, 1, 3, 4, 4};
         
        for( i = 0; i < 5; i++)
        {
         
                  for( j = i+1; j < 5; j++)
					  
					    if (array[i] == array[j])
                            {
								printf("%d ", array[i] );																
							}							  
        }
       
        return 0;
}

I guess you should break out of the loop as soon as it finds the repeated number

Code:

if(array[i] == array[j])
{
    printf("Found repeated number %d\n\n", array[i]);
    break;
}