C Codes

Hello World

/* hello.c: display a message on the screen */
 
#include <stdio.h>
 
int main(){
  printf("hello, C world\n");
  return 0;
}

• Text between /* and */ are comments.
• #include <stdio.h> to load the header file.
• There are many header files in the standard C library. ​http://en.wikipedia.org/wiki/C_standard_library
• Program always begins with main() function.
• main() returns a integer.

Compile with GNU C

[tulaneID@cypress1 ~]$ gcc hello.c

Compile with Intel C

[tulaneID@cypress1 ~]$ icc hello.c

Links for Tutorial

• ​ wikibooks

Examples of Jobscript

#!/bin/bash
#SBATCH --job-name=HelloC 
#SBATCH --qos=normal         
#SBATCH --time=0-00:10:00     ### Wall clock time limit in Days-HH:MM:SS
#SBATCH --nodes=1             ### Node count required for the job
#SBATCH --ntasks-per-node=1   ### Nuber of tasks to be launched per Node

echo Start Job
pwd

cat $SLURM_JOB_NODELIST

./a.out

echo End job

Parallel C

• OpenMP examples in C
• MPI examples in C

More Examples

• Approximate Pi
• Heat/Mass Transfer
• Stokes Flow In a Cavity
• Particle Strength Exchange Method