diff --git a/execution_example.csv b/execution_example.csv
new file mode 100644
index 0000000..aed220c
--- /dev/null
+++ b/execution_example.csv
@@ -0,0 +1,4 @@
+1 10 0 0
+2 103 3 0
+3 108 96 0
+...
diff --git a/simulator.c b/simulator.c
index 380dc00..0bcd6a6 100644
--- a/simulator.c
+++ b/simulator.c
@@ -1,8 +1,94 @@
+#include <stdlib.h>
+#include <stdio.h>
+
 #define RR_QUANTUM 2
 #define CNTXT_SWITCH 1
 
+enum pstate {
+    WAITING,
+    READY,
+    FINISHED
+};
+
+struct pinfo {
+    int id;
+    int arrival_time;
+    int execution_time;
+    int priority;
+    
+    int wait_time;
+    int completion_time;
+    enum pstate state;
+
+    struct pinfo * next_pinfo;
+};
+
+struct perf_info {
+    int total_time;
+    int total_nr_ctxt_switch;
+    int total_time_ctxt_switch;
+};
+
+struct pinfo * create_process(int id, int arrival_time, int execution_time, int priority) {
+    struct pinfo * info = {
+        id,
+        arrival_time,
+        execution_time,
+        priority,
+        0,
+        0,
+        WAITING,
+        NULL
+    };
+    return info;
+}
+
+struct perf_info * schedule_FCFS(struct pinfo * processes) {
+    int current_time = 0;
+    struct pinfo * process = processes;
+
+    struct perf_info * perf = {0, 0, 0};
+    
+    while (process != NULL) {
+        int wait_time = current_time - process->arrival_time;
+        if (wait_time < 0) {
+            wait_time = 0;
+        }
+        process->wait_time = wait_time;
+        process->completion_time = process->execution_time + process->wait_time;
+        current_time = process->arrival_time + process->completion_time;
+
+        process = process->next_pinfo;
+    }
+    perf->total_time = current_time;
+    
+    return perf;
+}
+
+
+struct pinfo * read_file() {
+    // TODO
+
+}
+
+void write_file(struct pinfo * process, struct perf_info * perf) {
+    // TODO
+}
+
+void print_perf(struct perf_info * perf) {
+    println("Total time: %d\n", perf->total_time);
+    println("Total number of context switches: %d\n", perf->total_nr_ctxt_switch);
+    println("Total time spent on context switching: %d\n", perf->total_time_ctxt_switch);
+}
+
 
 int main() {
+    struct pinfo * processes = read_file();
+
+    struct perf_info * perf = schedule_FCFS(processes);
+
+    write_file(processes, perf);
+    print_perf(perf);
 
     return 0;
 }
\ No newline at end of file