View Compilation Error

0_0_26251039_26016.c: In function 'main':
0_0_26251039_26016.c:9:3: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
   for(int i=0;i<n;i++){
   ^
0_0_26251039_26016.c:9:3: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_26251039_26016.c:13:11: error: redefinition of 'i'
   for(int i=0;i<n;i++)
           ^
0_0_26251039_26016.c:9:11: note: previous definition of 'i' was here
   for(int i=0;i<n;i++){
           ^
0_0_26251039_26016.c:13:3: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
   for(int i=0;i<n;i++)
   ^
0_0_26251039_26016.c:17:14: error: expected expression before '/' token
     ans=sum; //
              ^
0_0_26251039_26016.c:18:11: error: expected expression before '/' token
     end=i;//记录终点位置 
           ^
0_0_26251039_26016.c:18:11: error: stray '\274' in program
0_0_26251039_26016.c:18:11: error: stray '\307' in program
0_0_26251039_26016.c:18:11: error: stray '\302' in program
0_0_26251039_26016.c:18:11: error: stray '\274' in program
0_0_26251039_26016.c:18:11: error: stray '\326' in program
0_0_26251039_26016.c:18:11: error: stray '\325' in program
0_0_26251039_26016.c:18:11: error: stray '\265' in program
0_0_26251039_26016.c:18:11: error: stray '\343' in program
0_0_26251039_26016.c:18:11: error: stray '\316' in program
0_0_26251039_26016.c:18:11: error: stray '\273' in program
0_0_26251039_26016.c:18:11: error: stray '\326' in program
0_0_26251039_26016.c:18:11: error: stray '\303' in program