How do I create ASCII strings in my C program?

Use code like

#pragma convert("ISO8859-1") 
char * colinascii = "AAAAA";
... 
#pragma convert(pop) 

This generates data 0x414141414100.

Simple.

You can do similar if your main program is ASCII and you want to use an EBCDIC string.

 #pragma convert("IBM-1047")
    char * pEye = "CNBP";
    char * pName = "IFASMF.INMEM";
    int lName = strlen(pName);
#pragma convert(pop)