diff --git a/activations.c b/activations.c
new file mode 100644
index 0000000..91503ab
--- /dev/null
+++ b/activations.c
@@ -0,0 +1,13 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+
+float sigmoid(float weighted_sum)
+{
+    return 1.0 / (1 + exp(-(float)weighted_sum));
+}
+
+float sigmoid_derivative(float output)
+{
+    return 1.0;
+}
\ No newline at end of file
diff --git a/activations.h b/activations.h
new file mode 100644
index 0000000..4780681
--- /dev/null
+++ b/activations.h
@@ -0,0 +1,7 @@
+#ifndef ACTIVATIONS_H
+#define ACTIVATIONS_H
+
+float sigmoid(float weighted_sum);
+float sigmoid_derivative(float output)
+
+#endif
\ No newline at end of file
diff --git a/main.c b/main.c
index 6d6fab7..8d0276b 100644
--- a/main.c
+++ b/main.c
@@ -11,9 +11,10 @@ int main(int argc, char *argv[])
 
     printf("Bonjour et bienvenu ;)\n");
     int i;
-    for(i=1 ; i<= 30 ; i++)
+    /*for(i=1 ; i<= 30 ; i++)
     {
         printf("%dth generated fload = %f\n", i, random_float(0.0 , 1.0));
-    }
+    }*/
+
     return 0;
 }
\ No newline at end of file
diff --git a/network.h b/network.h
index 31c78f6..3fe68eb 100644
--- a/network.h
+++ b/network.h
@@ -5,8 +5,8 @@ typedef struct network Network;
 struct network
 {
     Neuron *layers_first_neurons; //first neuron of each layer of the network
-    Neuron *layers_last_neurons; //last neuron of each layer of the network
-    int number_layers; //keeps track of layers' number
+    //Neuron *layers_last_neurons; //last neuron of each layer of the network
+    int *neurons_per_layer; //keeps track of number of layers' neurons
 };
 
 Neuron *generate_layer(int n_neurons, int n_neurons_prev_layer);
diff --git a/training.c b/training.c
new file mode 100644
index 0000000..e69de29
diff --git a/training.h b/training.h
new file mode 100644
index 0000000..e69de29