Add echo

src/Makefile

@@ -1,6 +1,6 @@
 CC= gcc
-SRCFILES= cat.c touch.c yes.c mkdir.c
-OBJFILES= cat touch yes mkdir
+SRCFILES= cat.c touch.c yes.c mkdir.c echo.c
+OBJFILES= cat touch yes mkdir echo
 CFLAGS= -Wall -Wextra
 
 .PHONY: all clean
@@ -10,6 +10,7 @@ all:
 	$(CC) $(CFLAGS) touch.c -o touch
 	$(CC) $(CFLAGS) yes.c -o yes
 	$(CC) $(CFLAGS) mkdir.c -o mkdir
+	$(CC) $(CFLAGS) echo.c -o echo
 
 clean:
 	@rm ${OBJFILES}

src/echo.c

@@ -0,0 +1,65 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdbool.h>
+
+int main(int argc, char *argv[]) {
+  bool newline = true; // Enables newline in the end (to disable use arg -n)
+  bool escapes = false; // Enables backslash-escaped characters (to enable use arg -e)
+  for (int i = 1; i < argc; i++) {
+    if (!strcmp(argv[i], "-n")) {
+      newline = false;
+    } else if (!strcmp(argv[i], "-e")) {
+      escapes = true;
+    } else if (!strcmp(argv[i], "-E")) {
+      escapes = false;
+    } else {
+      if (escapes) {
+	for (size_t j = 0; j < strlen(argv[i]); j++) {
+	  if (argv[i][j] == '\\') {
+	    j++;
+	    switch(argv[i][j]) {
+	    case 'b':
+	      printf("\b");
+	      break;
+   	    case 'c':
+	      return 0;
+	    case 'e':
+	      printf("\e");
+	      break;
+	    case 'f':
+	      printf("\f");
+	      break;
+    	    case 'n':
+	      printf("\n");
+	      break;
+    	    case 'r':
+	      printf("\r");
+	      break;
+    	    case 't':
+	      printf("\t");
+	      break;
+	    case 'v':
+	      printf("\v");
+	      break;
+	    case '\\':
+	      printf("\\");
+	      break;
+	    default:
+	      printf("\\%c", argv[i][j]);
+	    }
+	  } else {
+	    printf("%c", argv[i][j]);
+	  }
+	}
+      } else {
+	printf("%s", argv[i]);
+      }
+      if (i < argc - 1)
+	printf(" ");
+    }
+  }
+  if (newline) {
+    printf("\n");
+  }
+  return 0;
+}