week7

week07/ex1.txt

@@ -0,0 +1,2 @@
+   text	   data	    bss	    dec	    hex	filename
+  53740	   7528	   1568	  62836	   f574	dwm

week07/ex2.c

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+#include <stdio.h>
+#include <stdlib.h>
+
+int main() {
+    int n;
+    scanf("%d", &n);
+    int *arr = malloc(sizeof(int) * n);
+    for (int i = 0; i < n; ++i) {
+        arr[i] = i;
+        printf("%d ", arr[i]);
+    }
+    printf("\n");
+    free(arr);
+}

week07/ex2.sh

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+#!/bin/sh
+
+gcc ex2.c -o ex2.out
+./ex2.out

week07/ex3.c

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+#include <stdlib.h>
+#include <stdio.h>
+#include <time.h>
+
+int main(){
+	//Allows you to generate random number
+	srand(time(NULL));
+
+	// Allows user to specify the original array size, stored in variable n1.
+	printf("Enter original array size:");
+	int n1=0;
+	scanf("%d",&n1);
+
+	//Create a new array of n1 ints
+	int* a1 = malloc(sizeof(int) * n1);
+	int i;
+	for(i=0; i<n1; i++){
+		//Set each value in a1 to 100
+		a1[i]=100;
+		
+		//Print each element out (to make sure things look right)
+		printf("%d ", a1[i]);
+	}
+
+	//User specifies the new array size, stored in variable n2.
+	printf("\nEnter new array size: ");
+	int n2=0;
+	scanf("%d",&n2);
+
+	//Dynamically change the array to size n2
+	a1 = realloc(a1, sizeof(int) * n2);
+
+	//If the new array is a larger size, set all new members to 0. Reason: dont want to use uninitialized variables.
+
+    for (int i = n1; i < n2; ++i) {
+        a1[i] = 0;
+    }
+	
+
+	for(i=0; i<n2;i++){
+		//Print each element out (to make sure things look right)
+		printf("%d ", a1[i]);
+	}
+	printf("\n");
+	
+	//Done with array now, done with program :D
+    free(a1);
+	
+	return 0;
+}

week07/ex3.sh

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+#!/bin/sh
+
+gcc ex3.c -o ex3.out
+./ex3.out

week07/ex4.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+// Assuming that previous size is provided, since there is no standard way to know the size of the allocated block
+void* myrealloc(void* ptr, size_t prev_size, size_t new_size) {
+    if (ptr == NULL) prev_size = 0;
+
+    char *res = malloc(new_size);
+    size_t copy_size = (prev_size < new_size ? prev_size : new_size);
+
+    for (size_t i = 0; i < copy_size; ++i) {
+        res[i] = ((char*) ptr)[i];
+    }
+
+    free(ptr);
+
+    return res;
+}
+
+// test myrealloc using ex3
+int main() {
+	//Allows you to generate random number
+	srand(time(NULL));
+
+	// Allows user to specify the original array size, stored in variable n1.
+	printf("Enter original array size:");
+	int n1=0;
+	scanf("%d",&n1);
+
+	//Create a new array of n1 ints
+	int* a1 = malloc(sizeof(int) * n1);
+	int i;
+	for(i=0; i<n1; i++){
+		//Set each value in a1 to 100
+		a1[i]=100;
+		
+		//Print each element out (to make sure things look right)
+		printf("%d ", a1[i]);
+	}
+
+	//User specifies the new array size, stored in variable n2.
+	printf("\nEnter new array size: ");
+	int n2=0;
+	scanf("%d",&n2);
+
+	//Dynamically change the array to size n2
+	a1 = myrealloc(a1, sizeof(int) * n1, sizeof(int) * n2);
+
+	//If the new array is a larger size, set all new members to 0. Reason: dont want to use uninitialized variables.
+
+    for (int i = n1; i < n2; ++i) {
+        a1[i] = 0;
+    }
+	
+
+	for(i=0; i<n2;i++){
+		//Print each element out (to make sure things look right)
+		printf("%d ", a1[i]);
+	}
+	printf("\n");
+	
+	//Done with array now, done with program :D
+    free(a1);
+	
+	return 0;
+}

week07/ex4.sh

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+#!/bin/sh
+
+gcc ex4.c -o ex4.out
+./ex4.out

week07/ex5.c

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+#include <stdio.h>
+
+int main() {
+    char *s;
+    char foo[] = "Hello World";
+    s = foo;
+    printf("s is %s\n", s);
+    printf("s[0] is %c\n", s[0]);
+    return (0);
+}

week07/ex5.sh

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+#!/bin/sh
+
+gcc ex5.c -o ex5.out
+./ex5.out