Program Error has me stuck

I'm a beginner with C++ and am writing a program that calculates whether a triangle is right, valid or invalid. On the coding for a right triangle i'm struggling( i figured this would be the easy part) If someone could help with this portion it would be greatly appreciated! Thanks

Code:

` int main()`

{

int a, b, c;

cout << "Please input three values for leg lengths: ";

cin >> a >> b >> c;

cin.ignore();

if ( a + b > c) {

cout << "That is not a valid triangle." << endl;

}

else if ( a*a + b*b = c*c) {

cout << "That's a right triangle." << endl;

}

cin.get();

}

Error occurs in the else if statement saying non-1value in assignment?

Again thanks in advance for any and all help!