View Compilation Error

0_0_34945544_15503.c: In function 'main':
0_0_34945544_15503.c:10:1: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
 for(int i = 5;i<=n;++i){
 ^
0_0_34945544_15503.c:10:1: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_34945544_15503.c:12:1: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
 for(int j = 1;j<=k;++j){
 ^
0_0_34945544_15503.c:23:9: error: redefinition of 'i'
 for(int i = k;i>=1;--i){
         ^
0_0_34945544_15503.c:10:9: note: previous definition of 'i' was here
 for(int i = 5;i<=n;++i){
         ^
0_0_34945544_15503.c:23:1: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
 for(int i = k;i>=1;--i){
 ^