You can change the loop control variable by any amount, positive or negative.

You could sum the first n integers backward as in the following example:

#include <stdio.h> int main(void) { unsigned long long sum = 0LL;// Stores the sum of the integers unsigned int count = 0; // The number of integers to be summed // Read the number of integers to be summed printf("\nEnter the number of integers you want to sum: "); scanf(" %u", &count); // Sum integers from count to 1 for(unsigned int i = count ; i >= 1 ; sum += i--); printf("\nTotal of the first %u numbers is %llu\n", count, sum); return 0;//from ww w .j av a 2 s .co m }

The loop counter is initialized to count, rather than to 1, and it's decremented on each iteration.

- for Statement
- Draw a box using for loop
- for Loop Control Options
- Use Nested for Loops to draw box
- Use Nested for Loops to sum successive integer sequences
- Nesting for loops