How about:
for (unsigned i = n ; i-- > 0 ; )
{
// do stuff with i
}
Top answer 1 of 16
119
How about:
for (unsigned i = n ; i-- > 0 ; )
{
// do stuff with i
}
2 of 16
15
for ( unsigned int loopIndex = n; loopIndex > 0; --loopIndex ) {
unsigned int i = loopIndex - 1;
...
}
or
for ( unsigned int loopIndex = 0; loopIndex < n; ++loopIndex ) {
unsigned int i = n - loopIndex - 1;
...
}
YouTube
youtube.com › watch
Reverse for Loop in C - C Programming Tutorial 51 🚀 - YouTube
Reverse for Loop in C - C Programming Tutorial 51 🚀► Master the Reverse for Loop in C! Learn how to use for loops with decrementing counter variables, and e...
Published April 18, 2020
forward and reverse for loops with C++ c - C++ Forum
Not as elegant as the other for loops, but it does work. ... FYI, Visual Studio 2019, build 16.11.2 requires the C++ language standard to be set to /std:c++latest to compile. Set the language standard to C++20 and VS spits out the following errors: While searching the bowels of the interwebs to find out the possibilities of a reverse ... More on cplusplus.com
c - iterating an array backwards in For loop condition to stop at 0 when using unsigned integers causing infinite loop - Stack Overflow
So the starting index should be ... 0, the for loop will not print anything, because i-1 == SIZE_MAX. ... The problem is that j >= 0 is always true because j is unsigned. When counting down to zero with an unsigned, I usually use postfix --: ... Unsigned value wraps around so when j == 0 and the loop does j--, j >= 0 is still true. ... Will print the string in reverse order : ... More on stackoverflow.com
How do you write a reverse loop in C using while, do - while or/and for loop?
I don't mean to sound like a dick, but if this is the type of question you turn to an online forum for, are you sure you want to be learning C? This sounds like a first assignment in a C programming class. There's nothing wrong with asking for help when you're stuck, but you haven't said what part you don't understand, which makes me think you were given an assignment and didn't read or listen to what you were supposed to. My very first job, 24 years ago, was tutoring C programming and I can guarantee that if you don't make an effort to read and understand the materials on your own, you're not going to get very far as a programmer. If you're just taking a mandatory class and don't care about learning C maybe you'll muddle through, but you'll annoy a whole bunch of people online by having them do your entire semester's assignments. If you google 'learn C' you'll get a number of good tutorial sites. Some of them let you edit and run code so you can tinker and make sure you understand what you're doing. If you've never programmed in any language before, make sure that you understand first what loops are and why you use them, and look at the differences between the types of loops in C. If you have prior programming experience (we learned to do reverse loops in BASIC on the Apple II in elementary school and the concept is the same) and just need to understand C's syntax, take a look at one of the online language references. If you're stuck, you can post "I'm trying to do ___ but I don't understand how ____ ...". It gets old having a bunch of posts that basically say "here's my homework, do it for me." More on reddit.com
6
0
July 8, 2017Is there a proper way to do a reverse for loop?
var i: usize = len; while (i > 0) { i -= 1; // do something } nothing dirty about while loops, that's some organic, gluten-free machine code right there. Healthy CPUs love that shit. More on reddit.com
11
12
May 29, 2023Videos
04:36
C program to print digits 1 to 5 in reverse order using a for loop ...
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Program to reverse string using for loop | C programming #shorts ...
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C++ Program to Reverse a Number using for loop - YouTube
08:54
Reverse number program using for loop | C++ Tutorial for Beginners ...
22:29
Forward for Loop in C - C Programming Tutorial 50 - YouTube
02:01
C Program to Print Natural Numbers from 1 to N In Reverse Order ...
Ashn
ashn.dev › blog › 2022-08-21-c-reverse-for-loop-iteration.html
Reverse For-Loop Iteration In C - ashn
August 21, 2022 - One can reverse-iterate from N-1 down to 0 in C using a for-loop of the form:
w3resource
w3resource.com › c-programming-exercises › for-loop › c-for-loop-exercises-37.php
C Program: Display the number in reverse order - w3resource
September 27, 2025 - printf("Input a number: "); // Prompt the user to input a number. scanf("%d", &num); // Read the input from the user. for(t = num; num != 0; num = num / 10){ // Loop to reverse the digits of the number. r = num % 10; // Extract the last digit (remainder when divided by 10). sum = sum * 10 + r; // Build the reversed number by adding the extracted digit. } printf("The number in reverse order is : %d \n", sum); // Print the reversed number. } ... Write a C program to reverse a number using recursion instead of loops.
Java2s
java2s.com › Code › C › Language-Basics › Reverseorderofforloop.htm
Reverse order of for loop : For « Language Basics « C / ANSI-C
Reverse order of for loop : For « Language Basics « C / ANSI-C
TutorialsPoint
tutorialspoint.com › learn_c_by_examples › reverse_counting_program_in_c.htm
Reverse Counting program in C
procedure counting() FOR value = END to START DO DISPLAY value END FOR end procedure · Now, we shall see the actual implementation of the program − · #include <stdio.h> int main() { int i, start, end; start = 1; end = 10; //reverse counting, we'll interchange loop variables for(i = end; i >= start; i--) printf("-\n", i); return 0; }
Forgetcode
forgetcode.com › c › 1913-reverse-the-string-using-for-loop
Reverse The String Using FOR Loop in C - Forget Code
Forget Code launches a powerful ... Loop #include <stdio.h> #include <string.h> int main(void) {char *str="ForgetCode"; printf("Reverse the String:"); for(int i=(strlen(str)-1);i>=0;i--) { printf("%c",str[i]); } return 0; }...
Coding Connect
codingconnect.net › home › reverse of a number using for loop in c
Reverse of a Number using For loop in C - Coding Connect
December 31, 2015 - #include<stdio.h> #include<conio.h> void main() { int i,n,r,s=0; clrscr(); printf("\n Enter The Number:"); scanf("%d",&n); //LOOP FOR FINDING THE REVERSE OF A NUMBER for(i=n;i>0; ) { r=i; s=s*10+r; i=i/10; } printf("\n The Reverse Number of %d is %d",n,s); getch(); }
GeeksforGeeks
geeksforgeeks.org › c language › c-program-to-traverse-an-array-in-reverse
C Program to Traverse an Array in Reverse - GeeksforGeeks
July 23, 2025 - Recursion can also be used to traverse an array in reverse order. It is less efficient than looping due to the overhead of function calls and additional memory usage. Below is the approach to use recursion to traverse the array in revese: Define a recursive function that takes the array and the current index as arguments. The base case is when all elements are traversed. Recursively call the function for ...
Cplusplus
cplusplus.com › forum › general › 279811
forward and reverse for loops with C++ c - C++ Forum
(I'm including SSCCE [ ... a container. I'll use a std::vector to illustrate 1. The old-school C/C++ for loop: ... Yet there is no way to do a reverse range-based for loop....
Codeforcoding
code4coding.com › home › c program to reverse a number using loops
C program to reverse a number using loops - Codeforcoding
November 8, 2024 - In this post, we are going to learn how to find reverse number of the given number in C programming language ... The program allows the user to enter a number and it displays the reverse pattern of the given number using for loop in C language
Medium
travcav.medium.com › why-reverse-loops-are-faster-a09d65473006
A look at reverse loops - Trav Cav - Medium
June 19, 2017 - Remember, always code for readability first, trust your compiler, and if you attempt any of the following make sure you benchmark. Reverse loops have been around a long time but have mostly been forgotten or ignored because these days nobody’s going to miss those extra few clock cycles and ...
Quora
quora.com › How-do-you-reverse-a-number-in-a-for-loop
How to reverse a number in a for loop - Quora
So we exit the loop. Now if we see the value that is stored in rev, we have 54321 which is the desired output. Hope this helps ! ... Write A Book Now With Qyx AI Book Creator! Write entire books quickly with Qyx AI Book Creator. World's most powerful and affordable AI ghostwriter. ... have been doing it for two decades when I joined quora · Author has 3.9K answers and 23.9M answer views · 6y · Originally Answered: How do I write a C program to reverse ...
Tutorjoes
tutorjoes.in › c_programming_tutorial › reverse_number_using_for_loop_in_c
Print the Reverse Number Using For Loop in C Programming
"printf" function to print the current value of n on each iteration of the loop, and decrement the value of n by 1 in each iteration. Finally, the program returns 0 to indicate that the program has completed successfully. #include<stdio.h> int main() { int n,i=1; printf("\nEnter the limit:"); scanf("%d",&n); for(n;n>=i;n--) { printf("\n%d",n); } return 0; } To download raw file Click Here
Top answer 1 of 7
11
for(j=i; j>0; j--) {
printf("%c", str[j-1]);
}
Would be another option.
For a beginner maybe easier to understand.
But the other answers would be better.
edit: i'd say the best would be for(j=i; j-- > 0;) by l3x.
decrementing j after checking if it is greater then 0.
Using a do{}while() loop would also work.
j = i;
do {
j--;
printf("%c", str[j]);
} while (j > 0);
2 of 7
7
size_t is an unsigned integer and it's never going to be less than 0. So
the condition in for loop is always true:
for(j=i;j>=0;j--)
You can modify the condition to (a bit ugly though):
for(j=i; j-- > 0;){
...
}
Note that in your condition, you are printing the \0 null byte too, which is a non-printable character. (since the j starts with a value equal to the string length). The above condition takes care of that too.
Also:
- you can use
strlen()instead of looping over it yourself. - Check the return value of
scanf()if input reading wad successful.
Sankalandtech
sankalandtech.com › Tutorials › C › reverse-number-for-loop-c.html
a program in c programming to print the reverse of any given number using a for loop.
Also in mathematical calculations and scientific simulations reversing number can help examine and understand composite data sets with accuracy and precision. This program includes taking any number from the user as input and then use the for loop to reverse the digits of the number and show the reverse number as output using printf() function.
TutorialKart
tutorialkart.com › c-programming › how-to-reverse-a-number-using-loops-in-c
How to Reverse a Number using Loops in C
February 18, 2025 - To reverse a number in C using loops, we repeatedly extract the last digit using the modulus operator (%), add it to the reversed number, and remove the last digit using division (/). This process continues until all digits are processed.
TutorialKart
tutorialkart.com › c-programming › how-to-reverse-a-string-using-loops-in-c
How to Reverse a String using Loops in C
February 18, 2025 - We create an empty array rev[] to store the reversed string. Using a for loop, we iterate from the last character of str to the first and copy each character to rev[].
Reddit
reddit.com › r/c_programming › how do you write a reverse loop in c using while, do - while or/and for loop?
r/C_Programming on Reddit: How do you write a reverse loop in C using while, do - while or/and for loop?
July 8, 2017 -
How would you execute the number from 1 to 10 reversed?
Top answer 1 of 3
42
I don't mean to sound like a dick, but if this is the type of question you turn to an online forum for, are you sure you want to be learning C? This sounds like a first assignment in a C programming class. There's nothing wrong with asking for help when you're stuck, but you haven't said what part you don't understand, which makes me think you were given an assignment and didn't read or listen to what you were supposed to. My very first job, 24 years ago, was tutoring C programming and I can guarantee that if you don't make an effort to read and understand the materials on your own, you're not going to get very far as a programmer. If you're just taking a mandatory class and don't care about learning C maybe you'll muddle through, but you'll annoy a whole bunch of people online by having them do your entire semester's assignments. If you google 'learn C' you'll get a number of good tutorial sites. Some of them let you edit and run code so you can tinker and make sure you understand what you're doing. If you've never programmed in any language before, make sure that you understand first what loops are and why you use them, and look at the differences between the types of loops in C. If you have prior programming experience (we learned to do reverse loops in BASIC on the Apple II in elementary school and the concept is the same) and just need to understand C's syntax, take a look at one of the online language references. If you're stuck, you can post "I'm trying to do ___ but I don't understand how ____ ...". It gets old having a bunch of posts that basically say "here's my homework, do it for me."
2 of 3
1
Or using a while loop: int i = 11; while (i-- > 1) { printf("%d\n", i); }
Tomclarke
tomclarke.dev › home › programming
Reverse Iteration with Range-Based For Loops in C++ – tomclarke.dev
A fairly minimal example, but for most cases this works beautifully! With the above code, iterating in reverse is as simple as it is forwards: // range-based for loop in reverse for (auto& i : reversed (values)) { std::cout << i; }