Assignment1 ZhangJie A00331569

mm.c

@@ -0,0 +1,106 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/wait.h>
+
+#define debug 0
+
+//caculate the mean value
+int mean(int* ptr, int length) 
+{
+     int mean=0;//mean value 
+ 		int i;
+     for(i=0; i<length; i++)
+	 {
+  	 mean+=ptr[i];// sumup      
+ 	  }
+        mean = mean/length;//the mean= sumup/count 
+
+     return mean;
+ }
+
+//caculate the median value
+ int median(int* ptr, int length)
+{
+    /*check the length of arry, if length is even,the median value is the mean of the 2 numbers in the middle. if length is odd, the median value is the number of length/2 +1 */
+	 int  md;//md is median value
+
+   	 if(length%2!=0)
+	{//odd 
+ 	md= ptr[length/2];
+	 }
+   	 else
+	{
+     	 md=(ptr[length/2]+ptr[(length/2)-1])/2; // md is the mean of 2 value in the median
+	}
+return md; 
+}
+// 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;
+}
+
+int main(int argc, char *argv[]) {
+
+    int i, length, *pt;
+    int getmean, getmedian;// for mean and median
+    // 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]);
+    }
+
+    // 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\n", pt[i]);
+    }
+
+/******************************add*******************************/
+fprintf(stdout, "All the value we calculate will be rundown \n");
+int rc=fork();
+if(rc<0)//error 
+{
+ fprintf( stderr, "can not fork, error\n");
+  exit(1);
+}
+else if (rc==0)
+{
+//run child process
+ fprintf(stdout, "I am child (pid: %d)\n", (int) getpid() );//print out the pid
+ getmedian = median(pt, length);//get calculate the median
+ fprintf(stdout, "the median value is %d \n" ,getmedian); //print out the Child should print the results of median()
+}
+else 
+ {
+ int wc=wait(NULL);//Make the parent wait until child has finished before printing results of mean()
+ fprintf(stdout, "hello, I am parent of %d (wc: %d) (pid:%d) \n" , rc, wc, (int) getpid());
+ getmean= mean(pt, length);  
+ fprintf(stdout, " the mean is %d\n", getmean);
+ }
+
+	return 0;
+}