View Compilation Error

0_0_6502148_3202.c: In function `main':
0_0_6502148_3202.c:7: error: `d' undeclared (first use in this function)
0_0_6502148_3202.c:7: error: (Each undeclared identifier is reported only once
0_0_6502148_3202.c:7: error: for each function it appears in.)