How to convert integer to string in C?

In C programming, there are several common methods to convert integers to strings. Below are some commonly used approaches.

1. Using the sprintf Function

sprintf is a versatile function that formats data into a string. Here, we can use it to convert an integer to a string.

c
#include <stdio.h>

int main() {
    int num = 123;
    char str[50];
    sprintf(str, "%d", num);
    printf("Integer converted to string: %s\n", str);
    return 0;
}

In this example, sprintf converts the integer num to the string str.

2. Using the itoa Function

itoa is a non-standard function but is available in many compilers (such as GCC and MSVC). It converts an integer to a string.

c
#include <stdio.h>
#include <stdlib.h>

int main() {
    int num = 123;
    char str[50];
    itoa(num, str, 10);  // The third parameter 10 indicates decimal
    printf("Integer converted to string: %s\n", str);
    return 0;
}

Here, the third parameter of itoa specifies the radix, which denotes the base used for the string representation (e.g., 10 for decimal).

3. Using the snprintf Function

snprintf is similar to sprintf but is safer because it allows specifying the target buffer size, thereby avoiding buffer overflow risks.

c
#include <stdio.h>

int main() {
    int num = 123;
    char str[50];
    snprintf(str, sizeof(str), "%d", num);
    printf("Integer converted to string: %s\n", str);
    return 0;
}

In this example, snprintf converts the integer to a string while ensuring it does not exceed the size of the buffer str.

Summary

Although sprintf and snprintf are standard library functions in C, itoa is not standard and may not be available in all compilers. Therefore, for portability, snprintf is a safer and more widely supported choice.