View Compilation Error

0_0_31926222_22262.c: In function 'main':
0_0_31926222_22262.c:11:9: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
         for(int j=2;j<=n;j++){
         ^
0_0_31926222_22262.c:11:9: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_31926222_22262.c:12:13: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
             for(int i=0;i<=40000;i++){
             ^
0_0_31926222_22262.c:20:17: error: redefinition of 'j'
         for(int j=i;j>=0;j--){
                 ^
0_0_31926222_22262.c:11:17: note: previous definition of 'j' was here
         for(int j=2;j<=n;j++){
                 ^
0_0_31926222_22262.c:20:9: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
         for(int j=i;j>=0;j--){
         ^