Compilare: user.cpp: In function ‘int main()’: user.cpp:20:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<strlen(a);i++) ^ user.cpp:23:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<strlen(a);i++) ^ user.cpp:39:27: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(a[i]==']') ^ user.cpp:10:13: warning: unused variable ‘j’ [-Wunused-variable] int t,i,j,ok; ^