Latest revision as of 10:15, 27 April 2011

Exam3 review

int main (int argc, char *argv[]) { FILE *infhd, *outfhd: if(argc <3){

 printf("error"
 return -1;}

infhd = fopen(argv[1]. "r'); outfhd = fopen(argv[2], "wb");

if(infhd ==NULL || outfhd == NULL){

 return -1;

}

int count [NUM_LETTER]; int iter; for(iter = 0; inter <NUM_LETTER; iter++){ count[iter] = 0; }

int ch;

while(!feof(infhd){ ch = fgetc(infhd);

ch = tolower(ch); //seperate header file OR if((ch >= 'a') && (ch <="z")){ count[ch-'a']++; } else if((ch >= "A') && (ch <= "Z')){ count[ch -"A']++; }

}

fwrite(count, sizeof(int), NUM_LETTER, outfhd);

fclose(outfhd); fclose(infhd); }

Question 2

//when not dynamically allocated, you have to make a copy (name)

Student *Student_create(char *n, double g) { Student *s = malloc(sizeof(Student)); s->name = strdup(n); or s->name = malloc(sizeof(n) +1 * sizeof(char)); strcpy(s->name, n);

s->gpa = g; return s; }

Student *Student_copy(Student *s) { return Student_create(s->name, s->gpa); }

void Student_destroy(Student *s) { free(s->name); //NOT OK free(s->gpa); free(s); }

void Student_assign (Student **dest, Student *src) { if((*dest) ==src) return; Student_destroy(*dest); //destroy destination pointing to *dest = Student_copy(src); }

// Student *s1 is a pointer //pointer to pointer you have to use &

Student_assign(&S3, S1);

Question 3

Node *List_search(Node *head, int v) { while(head != NULL) { if(head ->value == v) return head; head = head ->next; } return NULL; //never found }

OR

if(head == NULL) return NULL; if(head->value == v) return head; return List_search(head->next, v);

Node *List_reverse(Node *head) { Node *new_head = NULL;

while(head != NULL){ Node *tmp = head; head = head->next;

//next pointer of temp will be old head tmp->next = new_head; new_head = tmp; } return new_head; }

Node *List_delete(Node *head, int v) { //three cases

//empty list if(head == NULL) return NULL;

//value is in head if(head->value == v){ Node *new_head = head->next; Node_destroy(head); return new_head; }

//Iteration case while {curr-> next != NULL){

//Success case if(curr->next ->value == v){ Node *tmp = curr->next; Node_destroy(tmp); } curr = curr->next; }

//If we reached this point, there is no node of that value return head; }

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