View Compilation Error

0_0_3987320_15881.cpp:1: error: expected constructor, destructor, or type conversion before '<' token
0_0_3987320_15881.cpp:1: error: expected `,' or `;' before '<' token
0_0_3987320_15881.cpp: In function `int main()':
0_0_3987320_15881.cpp:7: error: `printf' undeclared (first use this function)
0_0_3987320_15881.cpp:7: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_3987320_15881.cpp:12: error: `fun' undeclared (first use this function)
0_0_3987320_15881.cpp: In function `int fun(int)':
0_0_3987320_15881.cpp:26: error: `int fun(int)' used prior to declaration