long integer question

[wingnut2626]

Lets say I have: long max_data, max_rows;How does this work? (If you need more of the code im looking at, please let me know.) max_data = (argc >= 4) ? strtol(argv[3], NULL, 10) : 512; max_rows = (argc >= 5) ? strtol(argv[4], NULL, 10) : 100;

[ofnuts]

You gave a ternary operator (? that evaluates a condition (argc >= 4), and if true return the item before the semicolon (strtol(argv[3], NULL, 10)) or otherwise returns the second item (512). So if you gave at least 4 arguments (so argv[3] exists) then it returns the conversion of the string in argv[3] to a long integer, interpreting it as a base 10 number. In other words this is shorthand for

long max_data;
if (argc >= 4) {
    max_data=strtol(argv[3], NULL, 10)
} else {
       max_data = 512
}

Or slightly better IMHO:

long max_data=512; // default value made more visible and unmissable
if (argc >= 4) {
    max_data=strtol(argv[3], NULL, 10)
}