Description
10 Points
This homework tests your understanding of the topics covered so far in C Programming –
Strings. Run the executable to understand the behavior of the program, make sure that the
search_list.txt file is in the same directory as the executable.
In this exercise you will learn how to search an array for the occurrence of a given string.
You will use the string comparison function
int strncmp(const char * cs, const char * ct, size_t n)
to find a given string (cs) in an array of strings using what is called linear search. That is, the
algorithm starts at the first element of a string array, compares the given string to the one in
that slot to see if they are equal. The strncmp function returns a zero if the two strings
match, or non-zero otherwise. If the result is non-zero then increment an index counter and
repeat. Here is the basic outline for the program.
Program: search_name.c
// open for reading the file search_list.txt (provided)
// setup a two dimensional array of char – names[60][60] this will be big enough to hold up
to 60 name even if the name is 59 characters long!
//This is NOT the best way to do this, but you need to work with pointers more to do it a
better, more space efficient way.
// set up a char buffer as a fixed array to hold a name to search for.
// write an algorithm that reads (fgets) the file, each line into the names array (names[i]).
// you should have every name in the file in one slot of the array.
// printf each name as it is read from the file and put into the array. printf(“%s\n”,
names[i]) to make sure it is in the array properly.
// now write an algorithm that searches through the array for a specific last name.
//there are several ways you can do this, but we will use a simple function here. You can set
up the search_name like this:
// char searchName[] = “Abraham”; looks for a name not in the list, or
// char searchName[] = “Wood”; looks for a name we know is in the list
//
// You can hard code these two cases to test your algorithm.
// You will need to first get the strlen(), string length, of the name to use to control the
number of characters used in the comparison, e.g. int n = strlen(name);
// Then the strncmp() function will only use the first n characters of names[i] to see if they
are the same lexicographical (alphabetic) order. If they are, the function returns zero so a
test for zero tells you if you have found the one you are looking for.
/**
Looks for the name in the array of names. Use the algorithm below.
*/
int find_string ( char names[][60], const char * name, int file_len) {
int n = strlen(name);
int found = 0;
while (found < file_len) {
if names[found] is the same as name then break;
increment found
}
if the name was found (hint: found < file_len) then return the found index number
else return -1 to indicate it was not found
}
int main() {
/**set up arrays and variables
call load_array(FILE * fid, char names[][60]);
// returns with array names[][] loaded from file as well as the number of names in file, 19
in our case.
//Get user input for a name to search for.
call find_string();
if found print success message on screen
else print no success message
**/
}
Submission Instructions: Submit the code on Canvas under hw6 Submission link as
search_name.c. Formatting, appropriate variable names, readability and commenting are all
considered while grading.
