You can use sprintf to do it, or maybe snprintf if you have it:
char str[ENOUGH];
sprintf(str, "%d", 42);
Where the number of characters (plus terminating char) in the str can be calculated using:
(int)((ceil(log10(num))+1)*sizeof(char))
Stack Overflow
stackoverflow.com › questions › 7021725 › how-can-i-convert-a-string-to-integer-in-c
How can I convert a string to integer in C? - Stack Overflow
I am trying to find out if there is an alternative way of converting a string to an integer in C. I regularly pattern the following in my code. char s[] = "45"; int num = atoi(s); Is th...
GeeksforGeeks
geeksforgeeks.org › c language › convert-string-to-int-in-c
Convert String to int in C - GeeksforGeeks
July 23, 2025 - There are 4 methods to convert a string to int which are as follows: ... The atoi() function in C takes a character array or string literal as an argument and returns corresponding value as integer. It is defined in the <stdlib.h> header file.
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How to convert strings to numbers in C - YouTube
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Convert A String To A Double, Int Or Long Int With atof(), atoi() ...
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ft_atoi, convert a string to an integer - YouTube
ft_atoi, convert a string to an integer
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Udemy
blog.udemy.com › home › it & development › software development › c string to int: simple ways to convert to numeric values
C String to Int: Simple Ways to Convert to Numeric Values - Udemy Blog
April 14, 2026 - In this case, the string is an array of characters pointed to by num. Then, we calculate the length of the string using the strlen() function. Next, we loop through the string and convert the string into decimal values.
Top answer 1 of 11
425
You can use sprintf to do it, or maybe snprintf if you have it:
char str[ENOUGH];
sprintf(str, "%d", 42);
Where the number of characters (plus terminating char) in the str can be calculated using:
(int)((ceil(log10(num))+1)*sizeof(char))
2 of 11
178
As pointed out in a comment, itoa() is not a standard, so better use the sprintf() approach suggested in the rival answer!
You can use the itoa() function to convert your integer value to a string.
Here is an example:
int num = 321;
char snum[5];
// Convert 123 to string [buf]
itoa(num, snum, 10);
// Print our string
printf("%s\n", snum);
If you want to output your structure into a file there isn't any need to convert any value beforehand. You can just use the printf format specification to indicate how to output your values and use any of the operators from printf family to output your data.
Reddit
reddit.com › r/learnprogramming › is there any function in c to convert an integer to a string?
r/learnprogramming on Reddit: is there any function in c to convert an integer to a string?
December 30, 2022 -
But not using ascii. if i give "56", it has to return 56 in int format
Jonathan Cook
cs.nmsu.edu › ~jcook › posts › cpp-string-conversions
C/C++: Converting Strings to Numbers • Jonathan Cook
January 25, 2023 - Notice that there is not a strtoi function – that’s OK, you can use the strtol and then typecast is to an int. int std::stoi( const std::string& str, std::size_t* pos = nullptr, int base = 10 ); long std::stol( const std::string& str, std::size_t* pos = nullptr, int base = 10 ); long long std::stoll( const std::string& str, std::size_t* pos = nullptr, int base = 10 ); unsigned long std::stoul( const std::string& str, std::size_t* pos = nullptr, int base = 10 ); unsigned long long std::stoull( const std::string& str, std::size_t* pos = nullptr, int base = 10 ); float std::stof( const std::string& str, std::size_t* pos = nullptr ); double std::stod( const std::string& str, std::size_t* pos = nullptr ); long double std::stold( const std::string& str, std::size_t* pos = nullptr );
Reddit
reddit.com › r/cplusplus › beginner needing help, converting string to integer.
r/Cplusplus on Reddit: Beginner needing help, converting string to integer.
November 9, 2022 -
Hello, I'm a first year CS student and am learning c++ at my university. I need to build a function that inputs a string from the user, "1234" for example, and then return the integer 1234.
I am not allowed to use the stoi function, and <iostream> and <string> are the only allowed libraries. I'm at a wall, I would appreciate any help! Thanks.
Top answer 1 of 4
8
What you want is stoi but since you can't use it, you will have to manually parse the string. The way it goes is, we inspect each individual character in string and if it is between '0' (0x30) and '9' (0x39), we subtract '0' from this value. Say the character is '4' (0x34) so the arithmatic will be 0x34 - 0x30 = 4 We do this for every letter and we have integer value. So something like define variable num start for loop from 0 till str.size() if character is between '0' and '9', subtract '0' and save in val num = num*10 + val end for loop
2 of 4
2
If you subtract '0' as a char from a string you will get the integer value because of how ascii works. A rough example would be "12345" - "0" would give you 12345 in integer form.
W3Schools
w3schools.com › c › c_type_conversion.php
C Data Type Conversion
C Reference C Keywords C <stdio.h> C <stdlib.h> C <string.h> C <math.h> C <ctype.h> C <time.h> C Examples C Real-Life Examples C Exercises C Quiz C Code Challenges C Practice Problems C Compiler C Syllabus C Study Plan C Interview Q&A · ❮ Previous Next ❯ · Share Link Copied · Sometimes, you have to convert the value of one data type to another type. This is known as type conversion. For example, if you try to divide two integers, 5 by 2, you would expect the result to be 2.5.
Weber State University
icarus.cs.weber.edu › ~dab › cs1410 › textbook › 8.Strings › c_string_numbers.html
8.2.2.6. C-Strings & Numbers
Advanced C-string to number conversion functions. The functions' increased flexibility requires additional arguments to configure the conversion process. For example, the base argument (called "radix" in some documentation) specifies the base of the digits in the C-string: 10 or decimal, 16 or hexadecimal, 2 or binary, etc.
Edureka Community
edureka.co › home › community › categories › c++ › easiest way to convert int to string in c
Easiest way to convert int to string in C | Edureka Community
May 31, 2022 - 179739/easiest-way-to-convert-int-to-string-in-c · Home · Community · Categories · C++ Easiest way to convert int to string in C · How to reverse a number in C++? Oct 28, 2024 · undefined reference to `get_string' cs50 library Sep 16, 2023 · fatal error: cs50.h (c language library) : No such file or directory Sep 16, 2023 ·
Microsoft Learn
learn.microsoft.com › en-us › dotnet › csharp › programming-guide › types › how-to-convert-a-string-to-a-number
How to convert a string to a number - C# | Microsoft Learn
Access to this page requires authorization. You can try changing directories. ... You convert a string to a number by calling the Parse or TryParse method found on numeric types (int, long, double, and so on), or by using methods in the System.Convert class.
Scaler
scaler.com › home › topics › convert string to int in c++
Convert String to Int in C++ - Scaler Topics
February 5, 2026 - If the starting character is a non-integer value, the stoi() function terminates, giving an error as shown in the output. ... A hands on AI engineering program covering Machine Learning, Generative AI, and LLMs - designed for working professionals & delivered by IIT Roorkee in collaboration ...
IBM
ibm.com › docs › de › i › 7.4.0
atoi() — Convert Character String to Integer
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WsCube Tech
wscubetech.com › resources › c-programming › programs › int-to-string
How to Convert Int to String in C? 5 Ways With Code
September 17, 2026 - Concatenate Two Strings · How to Reverse a String in C? (6 Programs) C Program to Reverse a Sentence · How to Convert String to Int in C? How to Convert Int to String in C? C Program to Reverse Array · How to Merge Two Arrays in C? Remove Space from String in C ·
Facebook
facebook.com › groups › cs50 › posts › 1769973409816363
Do anyone know how to convert a int to string on language ...
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ByteHide
bytehide.com › blog › turning a string into an int in c#: full guide
Turning a String into an Int in C#: Full Guide - ByteHide
March 27, 2025 - Let’s now dig deeper, delve into this world of string to int conversion. Fasten your seatbelts and read on. In C#, there are a few cool ways you can convert strings into integers. One such method is with the Parse() function.
W3Schools
w3schools.com › c › c_strings.php
C Strings
Since strings are actually arrays in C, you can access a string by referring to its index number inside square brackets [].
MDN Web Docs
developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Template_literals
Template literals (Template strings) - JavaScript | MDN
November 12, 2025 - Dollar signs can be escaped as well to prevent interpolation. ... Any newline characters inserted in the source are part of the template literal. Using normal strings, you would have to use the following syntax in order to get multi-line strings:
Pandas
pandas.pydata.org › docs › reference › api › pandas.get_dummies.html
pandas.get_dummies — pandas 3.1.0 documentation
Dummy-coded data. If data contains other columns than the dummy-coded one(s), these will be prepended, unaltered, to the result. ... Convert Series of strings to dummy codes.
Facebook
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How do you convert an int to a string in C??
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