Compilare: main.cpp: In function 'int main()': main.cpp:9:17: warning: unused variable 'nr' [-Wunused-variable] int n,m,i,j,nr=0,rez; ^~ main.cpp:7:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("ace.in","r",stdin); ^ main.cpp:8:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("ace.out","w",stdout); ^ main.cpp:11:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&cer); ^ main.cpp:12:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ main.cpp:15:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&mat[i][j]); ^