Finding sum of square of two numbers in an array - c

Question

My program should take a number from the user, and find the two numbers in an array such that the sum of their squares equals the user input squared. However, I'm having trouble doing this, as well as understanding all the errors I'm getting.
Here's my current attempt:
#include <stdio.h>
int numberaa;
scanf("%d",&numberaa);
int main()
{
int i,j;
int array[9] = {2,-4,6,3,9,0,-1,-9};
for (i = 0; i <= 8; i++)
for (j = 0; j <= 8; J++0)
firstone==i*i
secondone==j*j
if {
firstone+secondone=numberaa;
printf("The Numbers are %d and %d",j,i,numberaa);
return 0
};

Answer 1

Change
firstone+secondone=numberaa;
to
numberaa = firstone + secondone;
Ah! You need to grab a basic C book. For this time I am posting a correct code for you. Hope you will learn something.
#include <stdio.h>
int main()
{
int i,j;
int array[9] = {2,-4,6,3,9,0,-1,-9};
int numberaa;
scanf("%d",&numberaa);
for (i = 0; i <= 8; i++){
for (j = 0; j <= 8; J++0){
firstone = i*i
secondone = j*j
if(numberaa == firstone + secondone)
printf("The Numbers are %d and %d",j,i,numberaa);
}
}
return 0
}

Answer 2

You need to read through at least the introductory chapter of a book on C and work through the examples. That means typing them out (no, don't copy and paste), compiling them, and running them to understand what makes them work and what breaks them.
When you write your own code, always compile with warnings enabled, e.g. gcc -Wall -o my_executable_name my_code.c, and pay attention to the line numbers referenced in compiler errors and warnings.
I'll point out some locations of errors in your code below:
#include <stdio.h>
int numberaa; // Currently you're declaring this as a global. NO! not what you want.
scanf("%d",&numberaa); // This isn't going to happen out here. NO! NO NO NO!
int main() // Specify your parameters. int main(void)
{
int i,j;
int array[9] = {2,-4,6,3,9,0,-1,-9}; // why specify an array of 9 but store just 8 elements??
for (i = 0; i <= 8; i++) // These are the correct limits for array[9].
for (j = 0; j <= 8; J++0) // j and J are not the same. What is J++0 ????!! Also, read about "blocks" and try a for-loop example with more than one line.
firstone==i*i // WTF?? Have you even tried to compile this?
secondone==j*j // See line above.
if { // Likewise
firstone+secondone=numberaa; // Likewise again.
printf("The Numbers are %d and %d",j,i,numberaa); // How many formatting flags does your first argument have, and how many are to be inserted?
return 0 }; // again, have you tried to compile this?
Short version:
Semicolons
Assignment vs. equality
Scope of variables
Blocks, brace usage
syntax of if statements
You also aren't squaring the user input.
Efficiency: you only need to calculate firstone = i * i once for each i value, so take it outside the j loop.