Nested Loop in C

By | February 21, 2023

Prerequisite – Loops in C
A nested loop is a loop inside another loop. In C programming language, you can nest a loop inside another loop to perform repetitive tasks. The inner loop executes its entire cycle each time the outer loop executes one cycle.

Here is an example of a nested loop in C that prints a multiplication table:

for (int i = 1; i <= 10; i++) {     // outer loop for rows
    for (int j = 1; j <= 10; j++) { // inner loop for columns
        printf("%d ", i * j);
    }
    printf("\n");                   // print a newline after each row
}

In the above code, the outer loop iterates 10 times, once for each row in the multiplication table, and the inner loop iterates 10 times for each column in each row. The printf statement inside the inner loop prints the product of the row and column. After each row is printed, a newline character is printed to start a new line for the next row.

You can also have multiple nested loops in C to perform more complex tasks. Here is an example of a three-level nested loop:

for (int i = 1; i <= 3; i++) {           // outer loop for level 1
    for (int j = 1; j <= 3; j++) {       // inner loop for level 2
        for (int k = 1; k <= 3; k++) {   // innermost loop for level 3
            printf("%d %d %d\n", i, j, k);
        }
    }
}

In the above code, the outer loop iterates 3 times, once for each level-1 task. The inner loop iterates 3 times for each level-2 task, and the innermost loop iterates 3 times for each level-3 task. The printf statement inside the innermost loop prints the value of each loop variable for each task.

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Author: Mithlesh Upadhyay

I hold an M.Tech degree in Artificial Intelligence (2023) from Delhi Technological University (DTU) and possess over 4 years of experience. I worked at GeeksforGeeks, leading teams and managing content, including GATE CS, Test Series, Placements, C, and C++. I've also contributed technical content to companies like MarsDev, Tutorialspoint, StudyTonight, TutorialCup, and Guru99. My skill set includes coding, Data Structures and Algorithms (DSA), and Object-Oriented Programming (OOPs). I'm proficient in C++, Python, JavaScript, HTML, CSS, Bootstrap, React.js, Node.js, MongoDB, Django, and Data Science.