What Does C++ Int to String Mean?

In C++, int to string means converting a number (int) into text (string) so it can be used easily in output, display, or formatting.

int = number

string = text

So,

int → string

Example:

int a = 10;

string s = “10”;

The value is same, but data type is changed.
This process is called C++ int to string conversion.

Why We Use Int to String in C++?

We convert int to string when:

We want better output formatting
We need to add zeros before numbers
We work with Arduino
We combine numbers with text
We display numbers on screen

Method 1: C++ Int to String Using to_string() (Best Method)

				
					#include <iostream>
#include <string>
using namespace std;

int main() {
    int num = 25;
    string s = to_string(num);

    cout << s;
    return 0;
}

Explanation

num = 25

s = “25”

✔ Easy
✔ Beginner friendly
✔ Most used method

Method 2: C++ Int to String Using stringstream

				
					#include <iostream>
#include <sstream>
using namespace std;

int main() {
    int num = 40;
    string s;

    stringstream ss;
    ss << num;
    s = ss.str();

    cout << s;
    return 0;
}

Why Use This Method?

Works in old C++ (C++98)
Safe for exams
Very reliable

C++ Int to String with Leading Zeros

Sometimes we need output like:

005

010

099

Example Code

				
					#include <iostream>
#include <sstream>
#include <iomanip>
using namespace std;

int main() {
    int num = 5;

    stringstream ss;
    ss << setw(3) << setfill('0') << num;

    string result = ss.str();
    cout << result;

    return 0;
}

Output

005

C++ Int to String Zero Padding

Zero padding means:

number = 7

string = “007”

Used in:

Roll numbers
IDs
Timers
Counters

C++ Int to String Hex Conversion

				
					//Convert integer into hexadecimal string:
#include <iostream>
#include <sstream>
using namespace std;

int main() {
    int num = 255;
    stringstream ss;

    ss << hex << num;
    string s = ss.str();

    cout << s;
    return 0;
}
// COMMENTS
// Output
//ff

C++ Int to String in Arduino

Arduino Method

int num = 100;

String s = String(num);

C-Style Arduino Method

int num = 100;

char buffer[10];

itoa(num, buffer, 10);

C++ Int to Char (Single Digit Only)

int num = 7;

char ch = num + ‘0’;

7 → ‘7’

⚠ Works only for 0–9

Int to String C (Not C++)

C language uses character arrays.

				
					#include <stdio.h>

int main() {
    int num = 30;
    char str[10];

    sprintf(str, "%d", num);
    printf("%s", str);

    return 0;
}

Int to String C++98 (Old Standard)

Before to_string():

				
					#include <sstream>
using namespace std;

int num = 20;
stringstream ss;
ss << num;
string s = ss.str();

✔ C++98 compatible
✔ Exam safe

How to Convert String to Int in C++ Without stoi

				
					#include <sstream>
using namespace std;

string s = "123";
int num;

stringstream ss(s);
ss >> num;

FAQs – C++ Int to String

What is the easiest way to convert int to string in C++?

Use to_string().

How to add leading zeros in C++ int to string?

Use setw() and setfill().

Does to_string() work in old C++?

No, it needs C++11 or later.

How to convert int to string in Arduino?

Use String(num) or itoa().

How to convert string to int without stoi?

Use stringstream.

C++ Int to String Conversion – Simple Explanation with Examples