View Compilation Error

0_0_2962078_5138.cpp: In function `int main()':
0_0_2962078_5138.cpp:8: error: `a' undeclared (first use this function)
0_0_2962078_5138.cpp:8: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_2962078_5138.cpp: At global scope:
0_0_2962078_5138.cpp:24: error: expected unqualified-id before "return"
0_0_2962078_5138.cpp:24: error: expected `,' or `;' before "return"
0_0_2962078_5138.cpp:25: error: expected declaration before '}' token