View Compilation Error

0_0_24406800_698.c: In function 'get_first':
0_0_24406800_698.c:13:5: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
     for(int i=0; i<len; i++)
     ^
0_0_24406800_698.c:13:5: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_24406800_698.c:17:9: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
         for(int j=0; j<len; j++)
         ^
0_0_24406800_698.c: In function 'get_then':
0_0_24406800_698.c:37:5: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
     for(int i=0; i<len; i++)
     ^
0_0_24406800_698.c:38:9: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
         for(int j=0; j<len; j++)
         ^
0_0_24406800_698.c: In function 'main':
0_0_24406800_698.c:67:13: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
             for(int i=0; y; i++,y/=10)
             ^