Use a while loop and no temporary

src/one-body-sample.cc

@@ -243,13 +243,10 @@ int main(int argc, char *argv[]) {
     auto const &neumannFunction = functions.get("neumannCondition");
 
     // Find a (somewhat random) frictional node
-    size_t first_frictional_node;
-    for (size_t i = 0; i < frictionalNodes.size(); ++i) {
-      if (frictionalNodes[i][0]) {
-        first_frictional_node = i;
-        break;
-      }
-    }
+    size_t first_frictional_node = 0;
+    while (!frictionalNodes[first_frictional_node][0] &&
+           first_frictional_node < frictionalNodes.size())
+      ++first_frictional_node;
 
     for (size_t run = 1; run <= timesteps; ++run) {
       double const time = h * run;