View Compilation Error

0_0_7885979_23954.c: In function `main':
0_0_7885979_23954.c:11: error: `st' undeclared (first use in this function)
0_0_7885979_23954.c:11: error: (Each undeclared identifier is reported only once
0_0_7885979_23954.c:11: error: for each function it appears in.)
0_0_7885979_23954.c:11: error: syntax error before "a"
0_0_7885979_23954.c:21: error: `a' undeclared (first use in this function)