C: Difference between revisions

From XPUB & Lens-Based wiki
Line 40: Line 40:


<source lang="c">
<source lang="c">
for (int i=0; i<10; i++) {
int i;
     printf("Hello %d\n" % i);
for (i=0; i<10; i++) {
     printf("Hello %d\n", i);
}
}
</source>
</source>

Revision as of 21:25, 18 October 2010

... a programming language to follow B.

C is the core language of Unix and later GNU/Linux and the liberation of it's compiler software, gcc (the Gnu's alternative to the proprietary Unix C compiler (cc)), a foundation of the Free Software movement.

Variables

Variables in C are strictly typed meaning they always are one particular kind of representation of information (an integer number, a character, a string of text).

  • char
  • int
  • float
  • double
int i = 0;
printf("%d\n", i);

(short and long are "qualifiers" that then can be used before the word in as in:

short int foo;
long int bar;

In these cases the word int can be left out.)

Strings

Strings in C are arrays of characters.

char text[] = "pioneering jazz electronic organ recordings";
int textlen = strlen(text);
printf("%s id %d chars long, and starts with %c\n", text, textlen, text[0]);

Abstractly a string in C is simply a pointer; that is, a numeric memory location pointing to the first character of the text in the memory.

Loops

Like, Bash, C has a for loop:

int i;
for (i=0; i<10; i++) {
    printf("Hello %d\n", i);
}