Compilare: main.c: In function 'main': main.c:61:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("mergeheap.in","r",stdin),freopen("mergeheap.out","w",stdout),scanf("%d%d",&n,&m); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:61:39: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("mergeheap.in","r",stdin),freopen("mergeheap.out","w",stdout),scanf("%d%d",&n,&m); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:61:75: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] freopen("mergeheap.in","r",stdin),freopen("mergeheap.out","w",stdout),scanf("%d%d",&n,&m); ^~~~~~~~~~~~~~~~~~~ main.c:63:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&o); ^~~~~~~~~~~~~~ main.c:65:13: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a,&b),u[a]=I(b,u[a]); ^~~~~~~~~~~~~~~~~~~ main.c:67:13: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a),u[a]=D(u[a]); ^~~~~~~~~~~~~~ main.c:69:13: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a,&b),u[a]=M(u[a],u[b]),u[b]=NULL; ^~~~~~~~~~~~~~~~~~~