Compilare: main.cpp: In function 'void add()': main.cpp:11:13: warning: unused variable 'mex' [-Wunused-variable] int i,j,mex; ^~~ main.cpp: At global scope: main.cpp:25:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] main() ^ main.cpp: In function 'int main()': main.cpp:47:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation] if(i==1) ^~ main.cpp:49:13: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if' if(j!=1) ^~