Question

I am trying to write a program to find duplicate numbers in an array. I just don't get how to check and flag duplicates.

Answer 1

So you have an array (numArray), let us say it is of length 10, and its values are {1, 12, 5, 6, 5, 7, 1, 2, 9, 3}. You want to step through this array and spit out duplicate number. Are you wanting to print them or save them and print later?

int i, j, k;

for(i=0;i<9;i++){
for (j=(i+1);j<10;j++){
if (numArray[i] == numArray[j]){
printf("We have a duplicate of %d\n", numArray[i]);
}
}
}

Obviously there is a great deal more that could be done, but hopefully this will get you started until you flesh out more of a specific direction you'd like to go with this.