View Compilation Error

0_0_1384757_24646.cpp: In function `int main()':
0_0_1384757_24646.cpp:48: error: `a' undeclared (first use this function)
0_0_1384757_24646.cpp:48: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_1384757_24646.cpp:48: error: expected `;' before "endl"