6Programming TipsGet all information that your program needs from one option file, pass the option file to your program via command line (e.g. sas –sysparm ‘optionfile’ yourscript.sas), or at least define all the options using variables at the top your script.For any information that may change in different analyses, instead of fixed names, use variables. (e.g. set my data(keep=&markname) )Keep a good structure, use functionally independent macros and/or functions to organize your code. Don’t put every thing in one macro/function.%MACRO main();%macro1(); *get p value for markers;%macro2(); *merge with marker positions & allele frequencies;%MEND main;%main();Avoid name conflict. Name your variables and datasets using unique prefixes (e.g. QZ_temp).Write as little as you can.chrom loop; pheno loop; geno loop; yourmacro(indat=,y=,x=,covar=,method=,outdat=); end;end;end;Error handling.