Let's start with a simple analogy. Imagine there are 3 lines at a concert, and each line has 5 people in it. For *each line*, you need to visit *each person* in that line. The rows are labeled as *i* and the columns as *j*.   

 

# How can we do this using for-loops? 

Here comes the idea of using **nested** for loops. Using nested allows us to declare a for-loop within the body of another for-loop. The code below shows the syntax of the loop and explains it in detail.

#include <iostream>
using namespace std;

int main() {
 int count=0;
 for(int i=0;i<3;i++){
  
    for(int j=0;j<5;j++){
    
      count++;
    }
  
  }
 cout<<"Total number of people: "<<count<<endl;
}

Within the for loop on **line 6**, another for loop is written in the body on **line 8**. 

1. In simple terms, the for loop on line 6 runs the for loop on line 8 for every value of *i*.
2. The for loop on line 8 runs till the value of *j* increases from 0 to 4.
3. Then it moves back to the for-loop on line 6. 
4. Steps 1 to 3 are repeated until the value of *i* is equal to 2. 
5. The loop on line 8 cannot run if the loop on line 6 terminates completely. 

The slideshow below shows how this loop works when the value of *i=0*. This same process is repeated when *i=1* and *i=2*. 

How do you execute a nested for loop in C++?

Nested for loops in C++ iterate through each inner loop for every iteration of the outer loop.