Mã chấm: 268191

Main.cc: In function ‘float sopi(int)’:
Main.cc:9:20: error: expected initializer before ‘+=’ token
            float pi+=4*pow(-1,i)/(2*i+1);
                    ^~
Main.cc: In function ‘int main()’:
Main.cc:16:10: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~