Fixed segfault when no arguments given

input.c

@@ -17,7 +17,6 @@
 #define STAGE_2_ARG_COUNT 5
 #define STAGE_3_ARG_COUNT 5
 #define STAGE_4_ARG_COUNT 5
-#define OPEN_FILE_ERROR "Error: Unable to open file %s\n"
 
 enum stages getStage(char *stage) {  
     if (strcmp(stage, "1") == 0){
@@ -95,7 +94,7 @@ int getExpectedArgs(enum stages stage) {
 FILE *safeFileOpen(FILE **f, char *fileName, char *mode) {
     *f = fopen(fileName, mode);
     if (*f == NULL) {
-        fputs(OPEN_FILE_ERROR, stderr);
+        fprintf(stderr, "Error: Unable to open file %s\n", fileName);
         exit(EXIT_FAILURE);
     }
     return *f;

main.c

@@ -8,14 +8,7 @@
  * The polygon can be split using a pair of integers, which represent
  * the edge numbers that should be connected. This comes from stdin.
  *
- * To run the program type: 
- * ./voronoi1 dataset_file polygon_file output_file < splits
- * 
- * Options:
- *   dataset_file    required    Path to the dataset file (CSV)
- *   polygon_file    required    Path to the polygon file (txt)
- *   output_file     required    Output solution file
- *   splits          optional    Pairs of integers to split the edges
+ * To see valid input arguments, run ./voronoi2
  *
  */
 
@@ -69,6 +62,9 @@
 
 int main(int argc, char **argv) {
     /* Ensure input arguments are correct */
+    if (argc == 1) {
+        printArgError(STAGE_ERROR, "Incorrect usage.");
+    }
     enum stages stage = getStage(argv[1]);
     int expectedArgs = getExpectedArgs(stage);
     if (expectedArgs != argc) {