Compilare: main.c: In function 'main': main.c:74:8: warning: pointer targets in passing argument 1 of 'fgets' differ in signedness [-Wpointer-sign] fgets(c, 100, f); ^ In file included from /usr/include/stdio.h:936:0, from main.c:2: /usr/include/x86_64-linux-gnu/bits/stdio2.h:253:1: note: expected 'char * restrict' but argument is of type 'unsigned char *' fgets (char *__restrict __s, int __n, FILE *__restrict __stream) ^~~~~ main.c:75:11: warning: implicit declaration of function 'strlen' [-Wimplicit-function-declaration] s[0] = c[strlen(c) - 2]; ^~~~~~ main.c:75:11: warning: incompatible implicit declaration of built-in function 'strlen' main.c:75:11: note: include '<string.h>' or provide a declaration of 'strlen' main.c:75:18: warning: pointer targets in passing argument 1 of 'strlen' differ in signedness [-Wpointer-sign] s[0] = c[strlen(c) - 2]; ^ main.c:75:18: note: expected 'const char *' but argument is of type 'unsigned char *' main.c:76:18: warning: pointer targets in passing argument 1 of 'strlen' differ in signedness [-Wpointer-sign] s[1] = c[strlen(c) - 1]; ^ main.c:76:18: note: expected 'const char *' but argument is of type 'unsigned char *' main.c:77:9: warning: pointer targets in passing argument 1 of 'sscanf' differ in signedness [-Wpointer-sign] sscanf(s, "%u", &T); ^ In file included from /usr/include/features.h:367:0, from /usr/include/stdio.h:27, from main.c:2: /usr/include/stdio.h:448:12: note: expected 'const char * restrict' but argument is of type 'unsigned char *' extern int __REDIRECT_NTH (sscanf, (const char *__restrict __s, ^ main.c:90:9: warning: pointer targets in passing argument 1 of 'fgets' differ in signedness [-Wpointer-sign] fgets(c, 100, f); ^ In file included from /usr/include/stdio.h:936:0, from main.c:2: /usr/include/x86_64-linux-gnu/bits/stdio2.h:253:1: note: expected 'char * restrict' but argument is of type 'unsigned char *' fgets (char *__restrict __s, int __n, FILE *__restrict __stream) ^~~~~ main.c:91:19: warning: pointer targets in passing argument 1 of 'strlen' differ in signedness [-Wpointer-sign] s[0] = c[strlen(c) - 2]; ^ main.c:91:19: note: expected 'const char *' but argument is of type 'unsigned char *' main.c:92:19: warning: pointer targets in passing argument 1 of 'strlen' differ in signedness [-Wpointer-sign] s[1] = c[strlen(c) - 1]; ^ main.c:92:19: note: expected 'const char *' but argument is of type 'unsigned char *' main.c:93:10: warning: pointer targets in passing argument 1 of 'printf' differ in signedness [-Wpointer-sign] printf(s); ^