Compilare: user.c: In function ‘main’: user.c:16:1: warning: implicit declaration of function ‘memset’ [-Wimplicit-function-declaration] memset(digits, 0, 10 * sizeof(int)); ^ user.c:16:1: warning: incompatible implicit declaration of built-in function ‘memset’ [enabled by default] user.c:59:5: warning: passing argument 1 of ‘fputc’ makes integer from pointer without a cast [enabled by default] fputc(file2, ch = fgetc(file1)); ^ In file included from user.c:1:0: /usr/include/stdio.h:579:12: note: expected ‘int’ but argument is of type ‘struct FILE *’ extern int fputc (int __c, FILE *__stream); ^ user.c:59:5: warning: passing argument 2 of ‘fputc’ makes pointer from integer without a cast [enabled by default] fputc(file2, ch = fgetc(file1)); ^ In file included from user.c:1:0: /usr/include/stdio.h:579:12: note: expected ‘struct FILE *’ but argument is of type ‘char’ extern int fputc (int __c, FILE *__stream); ^ user.c:61:1: warning: passing argument 1 of ‘fputc’ makes integer from pointer without a cast [enabled by default] fputc(file2, smen); ^ In file included from user.c:1:0: /usr/include/stdio.h:579:12: note: expected ‘int’ but argument is of type ‘struct FILE *’ extern int fputc (int __c, FILE *__stream); ^ user.c:61:1: warning: passing argument 2 of ‘fputc’ makes pointer from integer without a cast [enabled by default] fputc(file2, smen); ^ In file included from user.c:1:0: /usr/include/stdio.h:579:12: note: expected ‘struct FILE *’ but argument is of type ‘char’ extern int fputc (int __c, FILE *__stream); ^ user.c:66:13: warning: passing argument 1 of ‘fputc’ makes integer from pointer without a cast [enabled by default] fputc(file2, a+'0'); ^ In file included from user.c:1:0: /usr/include/stdio.h:579:12: note: expected ‘int’ but argument is of type ‘struct FILE *’ extern int fputc (int __c, FILE *__stream); ^ user.c:66:13: warning: passing argument 2 of ‘fputc’ makes pointer from integer without a cast [enabled by default] fputc(file2, a+'0'); ^ In file included from user.c:1:0: /usr/include/stdio.h:579:12: note: expected ‘struct FILE *’ but argument is of type ‘int’ extern int fputc (int __c, FILE *__stream); ^ user.c:15:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%d", &length); ^