我已经用 PuTTy C++ 编写了共轭梯度代码。当我尝试编译它时，它会抛出下面的错误。
error: SCmathlib.h: No such file or directory
cg13.cc:11: error: '::main' must return 'int'
cg13.cc: In function 'int main(int, char**)':
cg13.cc:38: error: 'sin' was not declared in this scope
cg13.cc:39: error: 'exp' was not declared in this scope
cg13.cc:50: error: 'exp' was not declared in this scope
cg13.cc:60: error: 'exp' was not declared in this scope
cg13.cc:72: error: 'exp' was not declared in this scope
cg13.cc:83: error: 'dot' was not declared in this scope
cg13.cc:87: error: 'dot' was not declared in this scope
cg13.cc:131: error: 'fabs' was not declared in this scope
cg13.cc:132: error: 'fabs' was not declared in this scope
我怎样才能解决这个问题？