Homework SourseThe Task For this assignment you will write a rudimentary te
The Task
For this assignment you will write a rudimentary text editor that allows the user to edit 5 lines of text, where each line is no longer than 80 characters. The editor should allow the user to continue editing as long as desired and should print the current state of the edit buffer after each edit.
The editor is a \'line editor\' in that the user must edit one line at a time. The user can specify which line should be edited by choosing a line number from a menu.
The only two editing operations possible are to replace an entire line with a new line, or to replace a substring in the line with a new substring.
Musts
The program should not accept incorrect menu choices from the user. If the user creates a string that is longer than 80 characters the string should be truncated to fit the 80 character limit. The program should simply make no changes if the user tries to replace a substring that does not exist in the string.
Your program must use functions. Some functions are required, but you may make other functions as you see fit. You may not change the name, return type, or the parameter list types for required functions.
Required Function One
int replaceInString(char[] original, char[] substring, char[] replace);
This function causes the original string to be modified such that the first occurrence of substring is removed from the original string and the contents of replace are inserted in its place. replaceInString calls findSubString and insertString. The function returns 0 if the operation fails and 1 if the operation is successful.
Required Function Two:
int findSubString(char[] original, char[] toFind);
This function finds the first occurrence of toFind in original and returns an integer representing the index of the first element of the toFind substring in original. For example if toFind was \'cat\' and original was \'thundercat\' the function would return 7 since the begining of \'cat\' in \'thundercat\' is position 7. If the function does not find a substring it should return -1
note: do not use existing substring functions such as strstr as a solution for this function. Solve the algorithm yourself. You may use basic string functions such as strlen and strcat.
Required Function Three:
int insertString(char[] original, int start, int length, char[] toInsert);
This function replaces the contents of original with the following sequence of characters:
the characters from original up to position start-
the characters from toInsert
the characters from original starting at the character immediately after length.
Solution
#include <stdio.h>
#include <string.h>
#define ROW_LENTH 81
#define NUM_ROWS 5
void replaceLine(char line[]);
void printText(char text[][ROW_LENTH]);
int readFile(char filePath[], char text[][ROW_LENTH]);
int writeFile(char filePath[], char text[][ROW_LENTH]);
void removeTrailingHardReturn(char line[]);
void flushBuffer();
int getLine();
int replaceInString(char original[], char substring[], char replace[]);
int findSubString(char original[], char toFind[]);
void insertString(char original[], int start, int length, char toInsert[]);
int main(int argc, char *argv[]) {
//make the text buffer and zero it
char text[NUM_ROWS][ROW_LENTH];
for (int i = 0; i < NUM_ROWS; i++) {
text[i][0] = \'\\0\';
}
//check for file path arguments
if (argc == 2) {
printf(\"File argument detected. Reading file...\ \");
//read the file
if (readFile(argv[1], text)) {
printf(\"File read successfully\ \");
} else {
printf(\"File read unsuccessful\ \");
}
}
//continue asking for input until the user chooses to quit
char userInput = \'\\0\';
while(userInput != \'q\') {
//print out the text buffer
printText(text);
//ask for and get input
printf(\"Enter q to quit, r to replace a line, i to insert a substring over another\ \");
userInput = getchar();
switch (userInput) {
//if they want to quit
case \'q\':
printf(\"You have chosen to quit. Goodbye!\ \");
//save the text buffer back to the file
if (argc == 2) {
printf(\"Changes will now be saved to file\ \");
if (writeFile(argv[1], text)) {
printf(\"File written successfully\ \");
} else {
printf(\"Error writing file\ \");
}
}
break;
//if they want to replace an entire line
case \'r\':
//get the line
replaceLine(text[getLine()]);
break;
case \'i\':
//must have an empty statement because a variable cannot be
//declared as part of the same statement as a label
;
int lineNum = getLine();
//print that one line
printf(\"Line %c looks like:\ %s\ \", lineNum, text[lineNum]);
//get the substring to replace
char toReplace[ROW_LENTH];
printf(\"Please enter the subSring to replace in the line:\ \");
flushBuffer();
fgets(toReplace, ROW_LENTH, stdin);
removeTrailingHardReturn(toReplace);
//get the substring to replace with
char replaceWith[ROW_LENTH];
printf(\"Please enter the subSring to replace the old subString with:\ \");
fgets(replaceWith, ROW_LENTH, stdin);
removeTrailingHardReturn(replaceWith);
//do the replacement
if (replaceInString(text[lineNum], toReplace, replaceWith)) {
printf(\"Replacement successful!\ \");
} else {
printf(\"Replacement unsuccessful!\ \");
}
break;
default:
printf(\"Invalid input. Please try again\ \");
break;
}
}
return 0;
}
/*
This function overwrites one of the lines in the text
PARAMS:
line, a char array containing the line to overwrite
*/
void replaceLine(char line[]) {
flushBuffer();
printf(\"Please enter the text to replace the line with:\ \");
fgets(line, ROW_LENTH, stdin);
removeTrailingHardReturn(line);
}
/*
This function prints the all 5 lines for the user to see
PARAMS:
text, a 2D char array containing all 5 lines of the text
*/
void printText(char text[][ROW_LENTH]) {
//print all 5 lines
printf(\"The text currently looks like:\ \");
for (int i = 0; i < NUM_ROWS; i++) {
if (strlen(text[i]) == 0) {
printf(\"*LINE EMPTY*\ \");
} else {
printf(\"%s\ \", text[i]);
}
}
}
/*
This function reads lines of text from a file and puts them into the text array
PARAMS:
filePath, a string containing the path to the file with the data
text, a 2D char array containing all 5 lines of the text
*/
int readFile(char filePath[], char text[][ROW_LENTH]) {
//open the file
FILE* inFile = fopen(filePath, \"r\");
//check to see if the file exists
if (inFile != NULL) {
//read 5 lines or until end of file
for (int i = 0; i < 5 && !feof(inFile); i++) {
fscanf(inFile, \"%s\", text[i]);
removeTrailingHardReturn(text[i]);
}
//close file
fclose(inFile);
return 1;
} else {
//close file, return fail
fclose(inFile);
return 0;
}
}
/*
This function writes the user\'s text to a file
PARAMS:
filePath, a string containing the path to the file with the data
text, a 2D char array containing all 5 lines of the text
*/
int writeFile(char filePath[], char text[][ROW_LENTH]) {
//open the file
FILE* outFile = fopen(filePath, \"w\");
//check that it worked
if (outFile == NULL) {
return 0;
}else {
//write all 5 lines
for (int i = 0; i < 5; i++) {
fprintf(outFile, \"%s\ \", text[i]);
}
//close and return
fclose(outFile);
return 1;
}
}
/*
This function removes the newline character from the end of a string
PARAMS:
line, a char array containing the line remove the hard return from
*/
void removeTrailingHardReturn(char line[]) {
//remove the new line at the end
if (line[strlen(line) - 1] == \'\ \') {
line[strlen(line) - 1] = \'\\0\';
} else {
//if there was no newline, then flush the buffer because it\'s still in there
flushBuffer();
}
}
/*
This function removes everything from the input stream buffer so that
there is no erratic input to my menus from truncated input,
also removes the newlines from the end of input
*/
void flushBuffer() {
char input = \'\\0\';
do {
input = getchar();
} while (input != \'\ \' && input != EOF);
}
/*
This finction gets an integer input from 1 to the number of rows.
RETURNS
An integer from 1-5 (inclusive)
*/
int getLine() {
int validLine = 0;
int lineNum = -1;
//loop until the user input is valid
while (!validLine){
//ask for and get 1 character of input
printf(\"Please enter a line number to replace (1-5)\ \");
flushBuffer();
lineNum = getchar();
//check that it is a number between 1 and the number of rows (inclusive)
if (lineNum >= \'1\' && lineNum <= NUM_ROWS + 49) {
//if it is, return
return (int) lineNum - 49;
} else {
printf(\"Invalid input. Please try again.\ \");
}
}
return -1;
}
/*
This function utilizes findsubstring and insertstring to overwrite a substring
in a string with another
PARAMS
original, a character array that has the string that is to be changed
subString, a character array that contains the substring in original to be replaced
replace, a character array to replace the subString in original with
RETURNS
1 if successful (substring was found and replaced), 0 otherwise
*/
int replaceInString(char original[], char substring[], char replace[]) {
//find the location of the substring
int location = findSubString(original, substring);
//check to see if the substring is in the original string
if (location == -1) {
return 0;
} else {
//insert the string an return depending on success
insertString(original, location, strlen(substring), replace);
return 1;
}
}
/*
This function finds the first occurance of a substring in a string
PARAMS:
original, a char array of the string to search for the substring
toFind, a char array with the substring to search for
RETURNS
the index of the first character in the substring, or -1 if the substring was not found
*/
int findSubString(char original[], char toFind[]) {
//loop through the string
for (int i = 0; i < strlen(original); i++) {
//if it matches the first character begin looping through the substring
if (original[i] == toFind[0]) {
short match = 1;
//check that the following characters match the substring
for (int j = 1; j < strlen(toFind); j++) {
if (original[i + j] != toFind[j]) {
match = 0;
break;
}
}
//if they all match, return the location
if (match) {
return i;
}
}
}
return -1;
}
/*
This function inserts a string into another, overwriting part of that string
PARAMS:
original, a char array of the string to be changed
start, the index at which to insert the first character of the substring ebing inserted
length, the length of the original to be overwritten
toInsert, the substring to insert into the original string
RETURNS
1 if successful, 0 if not successful
*/
void insertString(char original[], int start, int length, char toInsert[]) {
if (start < 0 || length < 0) {
printf(\"Invalid parameter, no changes made\ \");
return;
}
//create a copy of the original string
char originalCopy[ROW_LENTH];
strcpy(originalCopy, original);
//end the string where the inserting string will start
original[start] = \'\\0\';
//add the inserted string
strcat(original, toInsert);
//add the end of the original string back to the end of the new string
for (int i = start + length; i < strlen(originalCopy); i++) {
int len = strlen(original);
original[len] = originalCopy[i];
original[len + 1] = \'\\0\';
}
}
