C++ Code Example: nested for loop

In the following program, a nested loop is used to check how often the loops are run through.

The program declares four integer variables: `a`, `b`, `c1`, and `c2`. `a` and `b` are set to 6 and 8, respectively. `c1` and `c2` are both set to 0 and will be used to keep track of the number of times each loop runs.

The outer loop, `for (int i = 10; i > a; i--)`, starts with `i` equal to 10 and decrements `i` by 1 until `i` is no longer greater than `a`. So, this loop runs 4 times. Each time the outer loop runs, `c1` is incremented by 1, so `c1` will equal 4 after the outer loop has finished running.

The inner loop, `for (int j = 0; j < b; j++)`, starts with `j` equal to 0 and increments `j` by 1 until `j` is no longer less than `b`. So, this loop runs 8 times for each iteration of the outer loop. Each time the inner loop runs, `c2` is incremented by 1, so `c2` will equal 32 after both loops have finished running (4 * 8 = 32).

The `if (i == j)` statement is checking if the values of `i` and `j` are equal. However, this condition will never be true because the outer loop decrements `i` while the inner loop increments `j`, so they will never have the same value.

Finally, the program outputs the results to the console using `cout` and returns 0, indicating that the program has executed successfully.

``````#include <iostream>
using namespace std;

int main() {
int a = 6, b = 8, c1 = 0, c2 = 0;

for (int i = 10; i > a; i--) {
c1++;
for (int j = 0; j < b; j++) {
c2++;
if (i == j) {
cout << "How many times the loops are run?" << endl;
cout << "first loop: " << c1 << "\nsecond loop: "
<< c2 << " (" << c1 << " * " << b << ")\n" << endl;
}
}
}

return 0;
}``````
Output
``````How many times the loops are run?
first loop: 4
second loop: 32 (4 * 8)``````