C Libraries and Makefiles

Libraries are very important in C because the C language supports only the most basic features that it needs. C does not even contain I/O functions to read from the keyboard and write to the screen. Anything that extends beyond the basic language must be written by a programmer. The resulting chunks of code are placed in libraries. We have seen the standard I/O, or stdio, library already: Libraries exist for math functions, string handling, time manipulation, and so on. Libraries also give you the ability to split up your programs into modules, which makes them easier to understand, test, and debug, and also makes it possible to reuse code from other programs that you write.


#include

#define MAX 10

int a[MAX];
int rand_seed=10;

int rand()
/* from K&R - produces a random number between 0 and 32767.*/
{
rand_seed = rand_seed * 1103515245 +12345;
return (unsigned int)(rand_seed / 65536) % 32768;
}

void main()
{
int i,t,x,y;

/* fill array */
for (i=0; i <>
{
a[i]=rand();
printf("%d\n",a[i]);
}

/* bubble sort the array */
for (x=0; x <>
for (y=0; y <>
if (a[y] > a[y+1])
{
t=a[y];
a[y]=a[y+1];
a[y+1]=t;
}

/* print sorted array */
printf("--------------------\n");
for (i=0; i <>
printf("%d\n",a[i]);
}

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