Compilare: user.c: In function ‘isWhitespace’: user.c:10:5: warning: implicit declaration of function ‘isspace’ [-Wimplicit-function-declaration] if (!isspace(*s)) ^ user.c: In function ‘main’: user.c:46:2: warning: implicit declaration of function ‘strdup’ [-Wimplicit-function-declaration] keys[0] = strdup(""); ^ user.c:46:10: warning: assignment makes pointer from integer without a cast [enabled by default] keys[0] = strdup(""); ^ user.c:71:23: warning: assignment makes pointer from integer without a cast [enabled by default] keys[index / 2] = strdup(token); ^ user.c:79:29: warning: assignment makes pointer from integer without a cast [enabled by default] values[index / 2 - 1] = strdup(token); ^ user.c:41:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("convertor.in", "r", stdin); ^ user.c:42:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("convertor.out", "w", stdout); ^