Generally, the current constitution is found at the beginning of the code for statutes, along with earlier constitutions and other organic laws (such as the declaration of independence and significant treaties.)
The U.S. Constitution is found in the first volume of the U.S.C. in a section labeled "Organic Laws of the United States." In the most recent, 2012 edition, the Constitution begins at page LXI and Constitutional amendments begin at page LXVI. (See Screencaps tab.) You can access the U.S.C. on HeinOnline and in print:
The California Constitution is found at the beginning of West's Annotated California Codes and Deering's California Codes Annotated. You can access these in print:
Access the Most Recent Version of the Code
Access the First Volume
Access Page LXI (for Constitution) and LXVI (for Amendments) Both Under Organic Laws
Don't be thrown off by the fact that the amendments are labeled as articles- technically, they are considered "Articles in addition to, and amendment of, the Constitution" and are labeled accordingly.