View Compilation Error

0_0_26785591_21688.c: In function 'main':
0_0_26785591_21688.c:13:9: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
         for(int i=0;i<a-1;i++){
         ^
0_0_26785591_21688.c:13:9: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_26785591_21688.c:19:9: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
         for(int i=0;i<a-1;i++){
         ^