Compilare: user.cpp: In function ‘int main()’: user.cpp:12:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(c==1)for(i=0;i<=strlen(s)-1;i++){if(s[i]=='+')if(s[i+1]=='0'||s[i+1]=='1'||s[i+1]=='2'||s[i+1]=='3'||s[i+1]=='4'||s[i+1]=='5'||s[i+1]=='6'||s[i+1]=='7'||s[i+1]=='8'||s[i+1]=='9') ^ user.cpp:25:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<=strlen(s)-1;i++){if(s[i]=='+')if(s[i+1]=='x'||s[i+1]=='y'||s[i+1]=='z'||s[i+1]=='t')sum=sum+1; ^ user.cpp:9:7: warning: unused variable ‘j’ [-Wunused-variable] int i,j,x,nr1=0,sum=0,n,nr,c; ^ user.cpp:9:9: warning: unused variable ‘x’ [-Wunused-variable] int i,j,x,nr1=0,sum=0,n,nr,c; ^