Quiz C2-2

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Question 1

What does the program below print out?

#include <stdio.h>

void super_cool_function(char *p){
  *p = *p - 4;
  *p++;
}

int main() {

  char a[6] = {'L','I','P','P','S', 4};
  for(int i =0; i < 6; i++){
    char * b = &a[i];
    super_cool_function(b);
  }
  printf("%s",a);
}

Question 2

What does the program below print out?

#include <stdio.h>
#include <string.h>

int main() {
  char str[] = "This will print";
  char * ptr;
  for( ptr = &str[strlen(str)-1]; ptr-str > 2; ptr--);
  printf("%s",ptr);
}

Question 3

This program isn’t nice and tells us to go away. Select the matching line(s) that will fix the program and make it say “Welcome”.

#include <stdio.h>
#include <string.h>

typedef struct {
  char **value;
  char *another_value;
} thing_t;

int main() {
  char *string1 = "a b c ";
  char **string_ptr = &string1;
  thing_t thing;
  thing.another_value = string1++;
  thing.value = &(thing.another_value);

  if (strcmp(string1, *(thing.value)) == 0) {
    printf("Welcome!");
  } else {
    printf("Go Away!!");
  }
}

Question 4

Consider the program below

int main(int argc, char * argv[]){

  for(char ** str = argv; *str; str++){
      printf("%c ", *(*str+1));
  }
  printf("\n");
}

Say that we compile this program to a.out and run it with the following arguments. What is the output?

./a.out foo bar baz boo bee bop