View Compilation Error

0_0_6678812_30265.c:3:21: algorithm: No such file or directory
0_0_6678812_30265.c:4: error: syntax error before "namespace"
0_0_6678812_30265.c:16: error: syntax error before "cmp"
0_0_6678812_30265.c:16: error: syntax error before "a"
0_0_6678812_30265.c: In function `cmp':
0_0_6678812_30265.c:18: error: `a' undeclared (first use in this function)
0_0_6678812_30265.c:18: error: (Each undeclared identifier is reported only once
0_0_6678812_30265.c:18: error: for each function it appears in.)
0_0_6678812_30265.c:18: error: `b' undeclared (first use in this function)