added todays assigment

.gitignore

+.nfs*

20230113/1/1.txt

+aaaaaa

20230113/1/2.txt

+aaabca

20230113/1/main.c

+#include <stdio.h>
+
+#include <errno.h>
+#include <string.h>
+#define err(s) fprintf(stderr, s "%s\n", strerror(errno))
+
+#define F1_STR "1.txt"
+#define F2_STR "2.txt"
+
+int main(void) {
+    int ret = 0;
+    FILE *f1;
+    if ((f1 = fopen(F1_STR, "r"))) {
+
+        FILE *f2;
+        if ((f2 = fopen(F2_STR, "r"))) {
+
+            char c1;
+            char c2;
+            int diff = 0;
+            while (fscanf(f1, "%c", &c1) != EOF &&
+                   fscanf(f2, "%c", &c2) != EOF &&
+                   !diff) {
+                if (c1 != c2) {
+                    diff = 1;
+                    printf("file 1: %c, file2: %c\n", c1, c2);
+                }
+            }
+            
+            fclose(f2);
+
+        } else {
+            ret = 1;
+            err(F2_STR ": ");
+        }
+
+        fclose(f1);
+    } else {
+        ret = 1;
+        err(F1_STR ": ");
+    }
+
+    return ret;
+}

20230113/2/1.txt

+abcdefghijk

20230113/2/2.txt

+abbdefgjklk

20230113/2/main.c

+#include <stdio.h>
+
+#include <errno.h>
+#include <string.h>
+#define err(s) fprintf(stderr, s "%s\n", strerror(errno))
+
+#define F1_STR "1.txt"
+#define F2_STR "2.txt"
+#define FOUT_STR "out.txt"
+
+int main(void) {
+    int ret = 0;
+    FILE *f1;
+    if ((f1 = fopen(F1_STR, "r"))) {
+
+        FILE *f2;
+        if ((f2 = fopen(F2_STR, "r"))) {
+
+            FILE *fout;
+            if ((fout = fopen(FOUT_STR, "w"))) {
+
+                char c1;
+                char c2;
+                while (fscanf(f1, "%c", &c1) != EOF &&
+                       fscanf(f2, "%c", &c2) != EOF) {
+                    if (c1 != c2) {
+                        printf("file 1: %c, file2: %c\n", c1, c2);
+                        fprintf(fout, "%c%c\n", c1, c2);
+                    }
+                }
+                fclose(fout);
+
+            } else {
+                ret = 1;
+                err(FOUT_STR ": ");
+            }
+            fclose(f2);
+        } else {
+            ret = 1;
+            err(F2_STR ": ");
+        }
+        fclose(f1);
+    } else {
+        ret = 1;
+        err(F1_STR ": ");
+    }
+
+    return ret;
+}

20230113/2/out.txt

+cb
+hj
+ik
+jl

20230113/3/1.txt

+aaa bbb ccc ddd eee

20230113/3/2.txt

+aaa b ccc dd eeee

20230113/3/main.c

+#include <stdio.h>
+
+#include <errno.h>
+#include <string.h>
+#define err(s) fprintf(stderr, s "%s\n", strerror(errno))
+
+#define F1_STR "1.txt"
+#define F2_STR "2.txt"
+
+int main(void) {
+    int ret = 0;
+    FILE *f1;
+    if ((f1 = fopen(F1_STR, "r"))) {
+
+        FILE *f2;
+        if ((f2 = fopen(F2_STR, "r"))) {
+
+            char s1[128];
+            char s2[128];
+            while (fscanf(f1, "%s", s1) != EOF &&
+                   fscanf(f2, "%s", s2) != EOF) {
+                if (strcmp(s1, s2) != 0) {
+                    puts(s2);
+                }
+            }
+
+            fclose(f2);
+        } else {
+            ret = 1;
+            err(F2_STR ": ");
+        }
+        fclose(f1);
+    } else {
+        ret = 1;
+        err(F1_STR ": ");
+    }
+
+    return ret;
+}