diff --git a/README.md b/README.md
new file mode 100644
index 0000000..3cc8c7e
--- /dev/null
+++ b/README.md
@@ -0,0 +1,5 @@
+# hellogit-pr
+
+This is a readme file
+
+## Try to start a pr
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..780b5d4
--- /dev/null
+++ b/main.c
@@ -0,0 +1,31 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <stdlib.h>
+
+int main(int argc, char *argv[]){
+    int start = 0;
+    int end = 0;
+    int sum = 0;
+    int opt;
+    char *optstring = ":s:e:";
+
+    while((opt = getopt(argc, argv, optstring))!= -1){
+        switch(opt){
+            case 's': start = atoi(optarg); break;
+            case 'e': end = atoi(optarg); break;
+            case ':': puts("Missing parameter"); exit(1);
+        }
+    }
+   
+    if(start<0 || end<=start){
+        puts("Parameter error"); exit(2);
+    }
+   
+    for(int i=start; i<=end; i++){
+        sum+=i;
+    }
+    printf("%d\n", sum);
+
+    return 0;
+}