added default branch

4 files changed, 149 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..5df624d
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,5 @@
+ed: ed.c
+	cc ed.c -o ed -ggdb
+clean:
+	rm ed
+
diff --git a/ed b/ed
new file mode 100755
index 0000000..b30760a
--- /dev/null
+++ b/ed
diff --git a/ed.c b/ed.c
new file mode 100644
index 0000000..3035c60
--- /dev/null
+++ b/ed.c
@@ -0,0 +1,141 @@
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+
+#define MAXCMD 256
+#define MAXLINE 2048
+#define MAXLINELEN 256
+
+char file[MAXLINE][MAXLINELEN];
+int linecount = 0;
+
+char command[MAXCMD];
+int cmdlen;
+
+int lineno = 0; 
+
+void eprint(char *str) {
+        fprintf(stderr, "%s\n", str);
+        exit(1);
+}
+
+void readcmd() {
+        char c;
+        while ((c = getchar()) != '\n' && cmdlen <= MAXCMD) {
+                command[cmdlen] = c;
+                cmdlen++;
+        }
+        command[cmdlen] = 0;
+}
+
+void emptystr(char *s) {
+        for (int i = 0; i < strlen(s); i++)
+                s[i] = 0;
+ }
+
+void emptycmd() {
+	emptystr(command);
+        cmdlen = 0;
+}
+
+void readfile(FILE *f) {
+        int i = 0;
+        char c;
+        while ((c = fgetc(f)) != EOF) {
+                if (c == '\n') {
+                        file[linecount][i] = 0;
+                        linecount++;
+                        i = 0;
+                } else {
+	                file[linecount][i] = c;
+	                i++;
+                }
+        }
+}
+
+void printfile(FILE *out, bool numbers) {
+        for (int i = 0; i < linecount; i++) {
+	        if (!numbers) fprintf(out, "%s\n", file[i]);
+        	else fprintf(out, "%d: %s\n", i, file[i]);
+        }
+}
+
+int readnum() { 
+	if (isdigit(command[0])) {
+		char num[MAXCMD] = {0};
+		int i;
+		for (i = 0; i < cmdlen && isdigit(command[i]); i++) {
+			num[i] = command[i];
+		}
+		num[i] = 0;
+		return atoi(num);
+	}
+	return -1;
+}
+
+void deleteline(int n) {
+	char nfile[MAXLINE][MAXLINELEN];
+	int nlinecount = 0;
+	for (int i = 0; i < linecount; i++) {
+		if (i != n) {
+			strcpy(nfile[nlinecount], file[i]);
+			nlinecount++;
+		}
+	}
+
+	for (int i = 0; i < nlinecount; i++) {
+		emptystr(file[i]);
+		strcpy(file[i], nfile[i]);
+	}
+	linecount--;
+}
+
+void runcmd(char *outpath) {
+	FILE *f;
+
+	int n;
+	if ((n = readnum()) != -1) {
+		if (n > linecount) printf("?\n");
+		lineno = n;
+		return;
+	}
+
+	switch (command[0]) {
+		case 'd':
+			deleteline(lineno);
+			break;
+		case 'P':
+			printfile(stdout, false);
+			break;
+		case 'N':
+			printfile(stdout, true);
+			break;
+		case 'w':
+			f = fopen(outpath, "w");
+			printfile(f, false);
+			fclose(f);
+			break;
+		case 'q':
+			exit(1);
+	}
+}
+
+int main(int argc, char **argv) {
+	FILE *f;
+        if (argc > 1) {
+                FILE *f = fopen(argv[1], "r+");
+                if (f == NULL) eprint("failed to open file");
+                readfile(f);
+                fclose(f);
+        } 
+        else eprint("no file given");
+
+        for (;;) {
+                readcmd();
+                runcmd(argv[1]);
+                emptycmd();
+        }
+}
+
diff --git a/tmp b/tmp
new file mode 100644
index 0000000..b5927a1
--- /dev/null
+++ b/tmp
@@ -0,0 +1,3 @@
+hello
+world
+line3