Compilare: user.c: In function ‘HugeMultiply’: user.c:7:1: warning: implicit declaration of function ‘memset’ [-Wimplicit-function-declaration] memset(C, 0, sizeof(C)); ^ user.c:7:1: warning: incompatible implicit declaration of built-in function ‘memset’ [enabled by default] user.c:17:1: warning: implicit declaration of function ‘memcpy’ [-Wimplicit-function-declaration] memcpy(A, C, sizeof(C)); ^ user.c:17:1: warning: incompatible implicit declaration of built-in function ‘memcpy’ [enabled by default] user.c: In function ‘main’: user.c:69:1: warning: implicit declaration of function ‘strlen’ [-Wimplicit-function-declaration] len1 = strlen(chA); ^ user.c:69:8: warning: incompatible implicit declaration of built-in function ‘strlen’ [enabled by default] len1 = strlen(chA); ^ user.c:33:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%d", &frecv[i]); ^