View Compilation Error

0_0_22636910_10976.c: In function 'main':
0_0_22636910_10976.c:8:5: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
     for(int i = 3; i <= 30; ++i)  
     ^
0_0_22636910_10976.c:8:5: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_22636910_10976.c:10:9: error: redeclaration of 'i' with no linkage
     int i, j, k, t, n;  
         ^
0_0_22636910_10976.c:8:13: note: previous definition of 'i' was here
     for(int i = 3; i <= 30; ++i)  
             ^