View Compilation Error

0_0_3187833_8910.c:2: error: syntax error before '&' token
0_0_3187833_8910.c: In function `change':
0_0_3187833_8910.c:5: error: `a' undeclared (first use in this function)
0_0_3187833_8910.c:5: error: (Each undeclared identifier is reported only once
0_0_3187833_8910.c:5: error: for each function it appears in.)
0_0_3187833_8910.c:6: error: `b' undeclared (first use in this function)
0_0_3187833_8910.c: In function `main':
0_0_3187833_8910.c:18: error: 'for' loop initial declaration used outside C99 mode