How to track a flow of a c program? - c

Question

I'ts more of a general question: how to handle the execution path of a c program, which consist of multiple functions?
For example, i have a following c program:
void test_if_statement(int num)
{
if (num > 0)
//do smth
;
else
//do smth else
;
}
int main(void)
{
int num;
printf("enter an int value:");
scanf("%d", &num);
test_if_statement(num);
return 0;
}
Currently i'm using something like this to see where did my function go in if statements:
void test_if_statement(int num)
{
if (num > 0)
printf("i'm here\n");
//do smth
else
printf("now i'm there\n");
//do smth else
}
How can I keep it simple and more universal?;)
Putting printf in every if-else pair seems unreasonably bulky...

Answer 1

This is usually a job for a debugger, most of which allow to step through the code one statement at a time. They also allow you to set breakpoints to pause execution at specific locations, watchpoints that pause execution when a variable changes, etc.
Without knowing your environment I can’t recommend a specific debugger to use. If you’re building code with gcc, then the companion debugger is (usually) gdb. You will need to use the -g flag when compiling to enable source-code level debugging. It’s not the friendliest debugger to use, but it’s pretty comprehensive. If you’re building in the Visual Studio environment on Windows, there should be a debugger as part of the IDE.

Answer 2

If you are using an IDE for purpose of writing code then it would have built-in facilities for debuggers, the only thing you would need to do is set break-points and then when the program is run your code would pause whenever a break-point is hit. IDEs also provide facilities to look up variable values at that instant.
If you are not using an IDE and your question is specifically w.r.t C you could consider using GDB. Have a look here to get a better idea of how to use GDB to debug programs.

Answer 3

There is nothing wrong using printf statements to track or log program flow for the purpose of learning, or testing during development. But a good debugger will probably serve the purpose just as well without having to add in-line code.
Depending on your environment there is a large list of debugger options available.
Following is an overview of debugging programs:
A debugger is a program that allows you to step through another
program one line at a time. This is very useful when trying to
identify incorrect code and analyze how a program "flows". Key
concepts include: Breakpoints, Stepping, and Viewing data.
Key things that you can use the debugger to determine are:
The flow of the program (what happens next on a line by line basis)
The creation of variables
The data being stored in each variable
The entering/leaving of functions
The calculations that are made
The entering of IF statements or ELSE statements
The LOOPING of code.
Much more detail here