Much of C’s syntax will feel very familiar coming from Java
Things that are similar: semicolons, {} blocks, function syntax, typed integer declarations, for loops, while loops, if statements
every program must have a main – it is the starting place of your program
int main(inst argc, char * argv[])
The return value is returned to the calling process, and it tells the process if the program completed successfully or not. We typically return 0 to indicate no errors occurred and -1 if there was an error.
The arguments of main give us access to the command line arguments with which the program was called.
argc tells us how many arguments have been passed to the programargv is an array of stringsC gives us access to memory at a low level through pointers, which can hold memory addresses
declare a pointer: int * p;. This creates a new variable p, which can hold the address of an integer in memory. The type of p is “integer pointer”.
To access memory at the location stored in a pointer, we use * to dereference it. In other words, *p can be treated like an integer variable and used as a value in expressions, or it can be assigned to on the left side of assignment statements.
Important, a declaration of a pointer only creates a location in memory that can hold an address, it does not also create a location for the integer value it refers to. Do not dereference a pointer without first assigning it to a valid location of the appropriate value.
To get the address of an existing variable, we use &.
Example: Create an integer variable x and a integer pointer xp, and then set xp to hold the address of x.
int x = 5;
int * xp = &x;