View Compilation Error

GCC/bin/../lib/gcc/mingw32/3.4.2/../../../../include/ctype.h: In function `int main()':
GCC/bin/../lib/gcc/mingw32/3.4.2/../../../../include/ctype.h:48: error: too few arguments to function `int isalnum(int)'
0_0_4432486_18604.cpp:155: error: at this point in file
0_0_4432486_18604.cpp:155: error: `isalnum(<expression error>)' cannot be used as a function