View Compilation Error

0_0_6551391_31788.c: In function `main':
0_0_6551391_31788.c:16: error: syntax error before '/' token
0_0_6551391_31788.c:21: error: `sum' undeclared (first use in this function)
0_0_6551391_31788.c:21: error: (Each undeclared identifier is reported only once
0_0_6551391_31788.c:21: error: for each function it appears in.)
0_0_6551391_31788.c:25: error: `res' undeclared (first use in this function)
0_0_6551391_31788.c:29: error: `to' undeclared (first use in this function)
0_0_6551391_31788.c:33: error: `from' undeclared (first use in this function)