Fix flushStdin() accepting variable arguments

main.c

@@ -36,7 +36,7 @@ typedef enum {
 	JACOBI = 0, GAUSS_SEIDEL = 1
 } Method;
 
-void flushStdin();
+void flushStdin(void);
 
 bool load(const char* filename, Matrix* A, Vector* b, Vector* x);
 Vector* solve(Method method, Matrix* A, Vector* b, Vector* x, double e);
@@ -209,7 +209,7 @@ int readMatrixLine(FILE* file, double* matrixLine, int maxCols) {
 	return col;
 }
 
-void flushStdin() {
+void flushStdin(void) {
 	int c;
 	while((c = getchar()) != '\n' && c != EOF && c != 0);
 }