0_0_28682735_2034.cpp: In function 'int main()': 0_0_28682735_2034.cpp:17:7: error: redeclaration of 'int i' int i=0,j=1,k; ^ 0_0_28682735_2034.cpp:13:11: note: 'int i' previously declared here for(int i=1;i<=n;++i){ ^