View Compilation Error

0_0_24220835_7567.cpp: In function 'int main()':
0_0_24220835_7567.cpp:5:12: error: expected initializer before '.' token
     int n,s.i;
            ^
0_0_24220835_7567.cpp:6:27: error: 'eof' was not declared in this scope
     while(scanf("%d",&n)!=eof)
                           ^
0_0_24220835_7567.cpp:7:5: error: 's' was not declared in this scope
     s=0;
     ^
0_0_24220835_7567.cpp:8:9: error: 'i' was not declared in this scope
     for(i=1;i<n;i++)
         ^
0_0_24220835_7567.cpp:10:9: error: 's' was not declared in this scope
         s=s+i;
         ^