View Compilation Error

0_0_28277694_13406.c:3:1: error: unknown type name 'bool'
 bool sushu(int n){
 ^
0_0_28277694_13406.c: In function 'sushu':
0_0_28277694_13406.c:10:18: error: 'false' undeclared (first use in this function)
  if(i<=1) return false;
                  ^
0_0_28277694_13406.c:10:18: note: each undeclared identifier is reported only once for each function it appears in
0_0_28277694_13406.c:12:14: error: 'true' undeclared (first use in this function)
  else return true;
              ^
0_0_28277694_13406.c: In function 'main':
0_0_28277694_13406.c:18:3: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
   for(int i=x;i<=y;i++){
   ^
0_0_28277694_13406.c:18:3: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code