CSCI3431-Assignment 1

mm.c

@@ -0,0 +1,112 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/wait.h>
+
+#define debug 0
+
+// Comparison function for qsort()
+int numcmp (const void *a, const void *b) {
+    int x = *((int*) a);
+    int y = *((int*) b);
+    if (x > y) return 1;
+    if (x < y) return -1;
+    return 0;
+}
+
+//Issues#2: Add a function, mean(),to mm.c to calculate the mean
+double mean (int *num, int len){
+
+  double sum = 0, mean = 0;
+
+  //using a for loop to add up all the values in input numbers
+  int i;
+
+  for( i = 0; i<len ;i++){
+    sum = sum + num[i];
+  }
+
+  //Find the mean
+  mean = sum / len;
+
+  return mean;
+}
+
+//Issues #3 Add a function, median(),to mm.c calculate the median
+double median(int *num, int len){
+
+  double median;
+  //If the array length is an even number
+  if(len%2==0){
+    median = (num[len/2]+num[len/2+1])/2.0;
+  }
+  //Otherwise the array length is a odd number
+  else{
+    median = num[(len+1)/2];
+  }
+  return median;
+}
+
+int main(int argc, char *argv[]) {
+
+    int i, length, *pt;
+
+    // Check for proper usage
+    if (argc < 2) {
+        fprintf(stderr, "%s: Aborting, not enough arguments.\n", argv[0]);
+        return (-1);
+    }
+
+    // Determine amount of numbers from argc
+    length = argc - 1;
+#if debug
+    fprintf(stderr, "%s: DEBUG: %d numbers were passed.\n", argv[0], length);
+#endif
+
+    // Allocate memory for array of number (and error check)
+    if ((pt = malloc(length * sizeof(int))) == NULL) {
+        fprintf(stderr, "%s: Could not allocate memory.\n", argv[0]);
+    }
+
+    //Issues #4 make mm.c fork(),have the parent call mean() and child call median()
+    int rc = fork();
+    //Check the rc value, if it return -1 means fork function fail
+    if(rc == -1){
+      fprintf(stderr,"Fork failed! No child!\n");
+    }else if (rc == 0){
+      //if rc equal to 0 which means fork succeed,the child is processing
+      //let child process print the result of median()
+      //Issues#5 Child process should print the results of median()
+      fprintf(stdout, "This is child processing!\n ");
+      fprintf(stdout, "The median value is %lf.\n",median(pt,length));
+    }else if (rc ==1){
+      //if rc equal to 1 means fork succeed, the parent is processing
+      //Issues #7 Make the parent wait until child has finished before pring the results of mean()
+      int wc = wait(NULL);
+      printf("I am waiting for my child. wc(:%d)\n",wc);
+      //let parent process print the result of mean()
+      //Issues#6 Parent process should print the results of mean()
+      fprintf(stdout,"This is parent processing!\n");
+      fprintf(stdout, "The mean value is %lf.\n",mean(pt,length));
+    }
+
+
+
+
+    // Read numbers into array
+    for (i = 0; i < length; i++) {
+        pt[i] = (int) strtol(argv[i+1], NULL, 10);
+    }
+
+    // Sort numbers
+    qsort(pt, length, sizeof(int), numcmp);
+
+    // Print out numbers
+    fprintf(stdout, "%s: Sorted output is: \n", argv[0]);
+    for (i=0; i<length; i++) {
+        fprintf(stdout, "%d ", pt[i]);
+    }
+    fprintf(stdout, "\n%s: FIN. \n", argv[0]);
+
+    return 0;
+}