C Language Header Reference

Quick lookup notes for `ctype.h` and `string.h` to support your C programming tutorial practice.

These PDFs are lookup guides while coding. They are intentionally separate from the two main notebooks.

ctype.h

Character classification and case conversion.

• Checks: isalnum, isalpha, isdigit, isxdigit, islower, isupper
• Whitespace and printable checks: isspace, isprint, isgraph, iscntrl, ispunct
• Case conversion: tolower, toupper

string.h

Core C string copy, concat, and compare tools.

• Copy: strcpy, strncpy
• Concatenate: strcat, strncat
• Compare: strcmp, strncmp