View Compilation Error

0_0_31310834_5630.c: In function 'main':
0_0_31310834_5630.c:15:9: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
         for(int i = 0; i <= 19; i++)
         ^
0_0_31310834_5630.c:15:9: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_31310834_5630.c:19:13: error: redefinition of 'i'
         int i = 0;
             ^
0_0_31310834_5630.c:15:17: note: previous definition of 'i' was here
         for(int i = 0; i <= 19; i++)
                 ^
0_0_31310834_5630.c:61:13: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
             for(int u = 0; u < shit;u++)
             ^