How to Convert int to string in C

Using sprint() function to convert int to string in C

#include <stdio.h>

int main(void)
{
	int num;
    int len;
	char mystr[10]; 

	printf("Please enter a number: ");
	scanf("%d", &num);

    //converting num to string
	sprintf(mystr, "%d", num);  
   len = sprintf(mystr, "%d", num);   

	printf("\n Num to string: %s", mystr);
    printf("\n Length of converted string: %d ", len);

	return 0;
}

Output

Please enter a number: 14

 Num to string: 14
 Length of converted string: 2 

1.2.Program Using sprint() to convert int to string with base

In this example, we are going to make use of the sprintf() function from the C standard library. This function is just like a format specifier that takes the format in which we want to print the input.

Syntax

int sprintf(char *str, const char *formatspec, [arg1, arg2, ... ])

Parameters

• str = is a pointer to a char str in which we will get output.
• formatspec = is is used to specify the format which we want for output.
• arg1, arg2 are integers to convert into a string.

C Program to Convert an Integer to a String using sprintf()

#include <stdio.h>

int main(void)
{
	int num;
    int len;
	char mystr[30];
		char mystr2[30]; 
		char str[30]; 

	printf("Please enter a number: ");
	scanf("%d", &num);

    //converting num to string
	sprintf(mystr, "%d", num);  
    
   
  
   

   printf("\n decimal value: %s", mystr);
    
   //hexadecimal value
  sprintf(mystr,"%x",num);
     
 printf("\n hexadecimal base : %s", mystr);
 //octal value
   sprintf(mystr,"%o",num);
 printf("\n octal value : %s", mystr);

	return 0;
}

Output

Please enter a number: 54312

 decimal value: 54312
 hexadecimal base : d428
 octal value : 152050

2. Convert int to string in C Using itoa() function

The itoa() C function allows us to convert integer numbers into null-terminated strings. In this example, we are going to make use of the itoa() function. This function can be used by just including the header file in your program. This function accepts an integer and returns a null-terminated string.

Note:- This function is not a standard function and on the Linux Posix system it may not work. It will work on windows systems for sure.

Syntax

char *12  itoa ( int val, char * str, int base );

Parmeters

• val: The integer number need to convert into string.
• str : It is a character array and pointer to buffer in memory where null terminated result string will store.
• Base : The base is a numeric value range from 2 to 32 categories as below
  • binary : if base is 2
  • octal : if base is 8
  • Decimal: if base is 10
  • Hex : base is 16

2.1 Using itoa() function to convert int to string in C

In this example, we are using itoa() function to convert int to string. This function is not defined in ANSI-C. But some compilers support it.

C Program to Convert an Integer to a String in C by using itoa() Function

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(void)
{
	int num;
	char mystr[30];
	int len;

	printf("Please enter a number: ");
	scanf("%d", &num);

	//converting num to string
	itoa(num, mystr, 2);
	printf("\n Binary value: %s", mystr);



	itoa(num, mystr, 8);
	printf("\n oct value: %s", mystr);

	itoa(num, mystr, 10);
	
	printf("\n Decimal value: %s", mystr);
		itoa(num, mystr, 16);
	printf("\n Hexa value: %s", mystr);
	

	return 0;
}

Output

Please enter a number: 54312

 Binary value: 1101010000101000
 oct value: 152050
 Decimal value: 54312
 Hexa value: d428

Summary

In this post we have learned how to convert int to string in C by using the following ways:

• sprint() function to convert int to string in C
• Using itoa() function to convert int to string in C