C Program to Convert int to char with Example

In C, you can convert an int to a char by using simple casting like char c = (char)intValue; or by adding '0' for digit characters like char c = intValue + '0';.

Examples

InputintValue = 5

Outputchar c = '5'

InputintValue = 65

Outputchar c = 'A'

InputintValue = 0

Outputchar c = '0'

How to Think About It

To convert an integer to a character in C, first decide if the integer represents a digit (0-9) or an ASCII code. For digits, add the character '0' to get the correct character. For ASCII codes, cast the integer directly to char.

Algorithm

1

Get the integer value to convert.

2

If the integer is a digit (0-9), add '0' to convert it to the corresponding character.

3

Otherwise, cast the integer directly to a char.

4

Store the result in a char variable.

5

Print or return the char value.

Code

c

#include <stdio.h>

int main() {
    int num = 5;
    char c = num + '0';
    printf("The char representation of %d is %c\n", num, c);
    return 0;
}

Output

The char representation of 5 is 5

Dry Run

Let's trace the example where num = 5 through the code.

1

Initialize integer

num = 5

2

Convert int to char

c = num + '0' = 5 + 48 = 53 (ASCII for '5')

3

Print result

Output: The char representation of 5 is 5

Step	num	Operation	Result
1	5	Initialize num	5
2	5	c = num + '0'	'5' (ASCII 53)
3	5	Print c	'5'

Why This Works

Step 1: Why add '0' to the integer?

Adding '0' (ASCII 48) to a digit integer converts it to the correct character digit because characters for digits are sequential in ASCII.

Step 2: Casting int to char

Casting an int directly to char converts the integer to the character with that ASCII code.

Step 3: Printing the character

Using %c in printf prints the character representation of the stored char variable.

Alternative Approaches

Direct cast for ASCII codes

c

#include <stdio.h>

int main() {
    int num = 65; // ASCII for 'A'
    char c = (char)num;
    printf("The char for ASCII %d is %c\n", num, c);
    return 0;
}

Use this when the int represents an ASCII code, not just digits.

Using sprintf to convert int to char string

c

#include <stdio.h>

int main() {
    int num = 5;
    char str[2];
    sprintf(str, "%d", num);
    printf("The char string is %s\n", str);
    return 0;
}

This converts int to a string, useful if you want a char array instead of a single char.

Complexity: O(1) time, O(1) space

Time Complexity

The conversion is a simple arithmetic or cast operation, so it runs in constant time.

Space Complexity

Only a single char variable is used, so space is constant.

Which Approach is Fastest?

Adding '0' or casting are both constant time and space; using sprintf is slower and uses more memory.

Approach	Time	Space	Best For
Add '0' to digit	O(1)	O(1)	Converting digit ints to char digits
Direct cast	O(1)	O(1)	Converting ASCII code ints to chars
sprintf to string	O(n)	O(n)	Converting int to char string