View Compilation Error

0_0_4763064_4167.c: In function `main':
0_0_4763064_4167.c:5: error: `_int64' undeclared (first use in this function)
0_0_4763064_4167.c:5: error: (Each undeclared identifier is reported only once
0_0_4763064_4167.c:5: error: for each function it appears in.)
0_0_4763064_4167.c:5: error: syntax error before "sum"
0_0_4763064_4167.c:7: error: `sum' undeclared (first use in this function)
0_0_4763064_4167.c:10: error: 'for' loop initial declaration used outside C99 mode
0_0_4763064_4167.c:13: error: 'for' loop initial declaration used outside C99 mode