Compilare: main.cpp: In function 'int main()': main.cpp:2:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] int main(){freopen("cmmdc.in","r",stdin);freopen("cmmdc.out","w",stdout);int a,b,r;scanf("%d%d",&a,&b);r=a%b;while(r!=0){a=b;b=r;r=a%b;}printf("%d",b);} ^ main.cpp:2:73: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] int main(){freopen("cmmdc.in","r",stdin);freopen("cmmdc.out","w",stdout);int a,b,r;scanf("%d%d",&a,&b);r=a%b;while(r!=0){a=b;b=r;r=a%b;}printf("%d",b);} ^ main.cpp:2:103: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] int main(){freopen("cmmdc.in","r",stdin);freopen("cmmdc.out","w",stdout);int a,b,r;scanf("%d%d",&a,&b);r=a%b;while(r!=0){a=b;b=r;r=a%b;}printf("%d",b);} ^