Compilare: user.c: In function ‘main’: user.c:15:1: warning: implicit declaration of function ‘memset’ [-Wimplicit-function-declaration] memset(digits, 0, 10 * sizeof(int)); ^ user.c:15:1: warning: incompatible implicit declaration of built-in function ‘memset’ [enabled by default] user.c:55:1: warning: implicit declaration of function ‘abs’ [-Wimplicit-function-declaration] absLength = abs(length - sigma); ^ user.c:14:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%d", &length); ^