Assignment 7

assignment7.txt

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+Ava N.
+July 7, 2015
+
+Assignment 7
+
+1. ++*p increments value at location p point to, then evaluates (stores) to incremented value.
+*p++ evaluates the value at location p points to, then advances p. (*p)++ evaluates the value at the location p points to, then increments that value.
+
+
+2. The left to right or right to left order for operator precedence is not guarenteed.
+
+3. The advantages of using pointers are that they provide a way for functions to modify their calling arguments, pointers support dynamic memory allocation, and they increase efficiency when working with arrays. 
+
+
+4. (*int, &char, 10, 0 or 1, ) (looking at the types: *X==y answer=o or 1 or invalid)
+4.1: char *
+4.2: 1
+4.3: 1
+4.4: pointer
+4.5: int *
+4.6: int
+4.7: pointer
+4.8: char*
+4.9: invalid
+4.10: invalid

reverse.c

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+//Ava N.
+//In a program reverse.c, write a string reversal function using pointers that takes only a string as input, creates 2 pointers, performs a string reversal using those pointers, and prints out the reversed string. Your driver should take a string input by the user using fgets().
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int main(){
+	char arr[50];
+	char *p1;
+	char *p2;
+	char temporary;
+
+	printf("Input a string that is under 50 letters long. \n");
+
+	fgets(arr, sizeof(arr), stdin);
+	printf("\n");
+	p1 = &arr;                 /* points to first character in string */
+	p2 = &arr[strlen(arr)-1];  /* points to last character in string */
+
+
+/* Diagnostic purposes ... 
+
+	printf("\nThe following is diagnostic *****\n");
+	printf("You input: %s\n",arr);
+	printf("Sizeof(arr) is %d\n",sizeof(arr));
+	printf("String Length (including null) is: %d\n",strlen(arr));
+	printf("first character is: %c\n",arr[0]);
+	printf("last character is: %c\n",arr[strlen(arr)-2]);
+	printf("P1 and P2 point to char: %c %c\n",*p1,*p2);
+	printf("arr[0] is: %c\n",arr[0]);
+	printf("p1 address is %d\n",p1);
+	printf("p2 address is %d\n",p2);
+	printf("end diagnostic!**** \n\n");
+*/
+/* End diagnostic */
+
+
+
+
+	while (p1 <= p2){
+		temporary = *p2;
+		*p2 = *p1;
+		*p1 = temporary;
+		*p1++;
+		*p2--;
+	}
+
+	printf("Here is the reversed of what you wrote: %s\n", arr);
+
+}

str_functions.c

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+//Ava N.
+//Write a program that implements 2 functions: (strcat() and) strcmp(). Use pointers and write the main function to execute both of these function on 2 strings. 
+
+#include <stdio.h>
+#include <string.h>
+
+char *characters(char* var1, char* var2) {
+
+	return characters;
+}
+//strcmp()
+//strcat()
+
+
+int main (){
+	//int characters;
+	char *var1="Welcome";
+	char *var2="NY!";
+
+	//);
+	//characters = strcmp(var1, var2);
+
+	printf("Text from var1 + var2: |%s %s|\n", var1, var2);
+
+	return(0);
+}