Practical Malware Analysis

Recognizing Loops

Loops and repetitive tasks are very common in all software, and it is important that you are able to recognize them.

Finding for Loops

The for loop is a basic looping mechanism used in C programming. for loops always have four components: initialization, comparison, execution instructions, and the increment or decrement.

Example 6-12 shows an example of a for loop.

Example 6-12. C code for a for loop

int i;

for(i=0; i<100; i++)
{
   printf("i equals %d\n", i);
}

In this example, the initialization sets i to 0 (zero), and the comparison checks to see if i is less than 100. If i is less than 100, the printf instruction will execute, the increment will add 1 to i, and the process will check to see if i is less than 100. These steps will ...