View Compilation Error

0_0_20796761_18392.c:2:1: error: unknown type name 'bool'
 bool leap(int n)
 ^
0_0_20796761_18392.c: In function 'leap':
0_0_20796761_18392.c:4:44: error: 'true' undeclared (first use in this function)
     if((n%4==0&&n%100!=0)||n%400==0)return true;
                                            ^
0_0_20796761_18392.c:4:44: note: each undeclared identifier is reported only once for each function it appears in
0_0_20796761_18392.c:5:17: error: 'false' undeclared (first use in this function)
     else return false;
                 ^
0_0_20796761_18392.c: In function 'main':
0_0_20796761_18392.c:20:13: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
             for(int i=1;i<=18;i++)
             ^
0_0_20796761_18392.c:20:13: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_20796761_18392.c:25:13: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
             for(int i=0;i<18;i++)
             ^