Compilare: user.cpp: In function ‘int main()’: user.cpp:16:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<strlen(r)) ^ user.cpp:19:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<strlen(r) && r[i]==' ' || r[i] =='(') ^ user.cpp:19:27: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] while(i<strlen(r) && r[i]==' ' || r[i] =='(') ^ user.cpp:40:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(strchr(r+j,')')!=NULL && j<strlen(r)) ^ user.cpp:44:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j<strlen(r) && r[j]>='0' && r[j]<='9') ^ user.cpp:51:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j<strlen(r)) ^ user.cpp:55:57: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(r[j+1]>='0'&&r[j+1]<='9' && j<strlen(r)) ^ user.cpp:77:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<strlen(r)) ^ user.cpp:81:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<strlen(r) && r[i]<='z' && r[i]>='a') ^ user.cpp:91:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<strlen(r) && r[i]>='0' && r[i]<='9') ^ user.cpp:99:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j<strlen(r) && r[j]<='z' && r[j]>='a') ^ user.cpp:102:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j<strlen(r) && r[j]>='0' && r[j]<='9') ^