如何只显示字符串的前几个字符

string = "Hello, World!"
n = 5
substring = string[:n]
print(substring)

String string = "Hello, World!";
int n = 5;
String substring = string.substring(0, n);
System.out.println(substring);

let string = "Hello, World!";
let n = 5;
let substring = string.slice(0, n);
console.log(substring);

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

int main() {
    string str = "Hello, World!";
    int n = 5;
    string substring = str.substr(0, n);
    cout << substring << endl;
    return 0;
}