Display Number Sequences in C

Displaying number sequences is a simple way to practice for loops, step values and formatting. The first example prints 1 to 100 with a line break after every ten numbers.

Display 1 to 100 in Rows of 10 Top ↑

#include <stdio.h>

int main(void) {
    for (int i = 1; i <= 100; i++) {
        printf("%3d ", i);

        if (i % 10 == 0) {
            putchar('\n');
        }
    }

    return 0;
}

The integer remainder operator % is enough here; fmod() is for floating-point values.

Print Even Numbers Top ↑

#include <stdio.h>

int main(void) {
    for (int i = 2; i <= 10; i += 2) {
        printf("%d ", i);
    }

    putchar('\n');
    return 0;
}

Display Numbers with Leading Zeros Top ↑

#include <stdio.h>

int main(void) {
    for (int i = 1; i <= 10; i++) {
        printf("%03d\n", i);
    }

    return 0;
}

%03d requests a field width of 3 and fills unused leading positions with zeros.

Print Odd Numbers Top ↑

#include <stdio.h>

int main(void) {
    for (int i = 1; i <= 10; i += 2) {
        printf("%d ", i);
    }

    putchar('\n');
    return 0;
}

Print Numbers in Reverse Order Top ↑

#include <stdio.h>

int main(void) {
    for (int i = 10; i >= 1; i--) {
        printf("%d ", i);
    }

    putchar('\n');
    return 0;
}

Display Negative Numbers Top ↑

#include <stdio.h>

int main(void) {
    for (int i = -1; i >= -10; i--) {
        printf("%d ", i);
    }

    putchar('\n');
    return 0;
}

Continue with Fibonacci numbers or review the for loop.

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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