0_0_34115955_23778.cpp:2:2: error: invalid preprocessing directive #defint #defint pi 3.1415926 ^ 0_0_34115955_23778.cpp: In function 'int main()': 0_0_34115955_23778.cpp:7:9: error: 'pi' was not declared in this scope sum=3/4*pi*d; ^