# How to Pad an Integer Number With Leading Zeroes in C#?

Given a Number N, the task is to pad this number with P number of leading zeros in C#.

Examples:

```Input: N = 123 , P = 4
Output: 0123

Input: N = -3 , P = 5
Output: -00003
```

Method 1: Using string Format() method : The Format() method is used to replace one or more format items in the specified string with the string representation of a specified object.

Step 1: Get the Number N and number of leading zeros P.

Step 2: Convert the number to string and to pad the string, use the string.Format() method with the formatted string argument “{0:0000}” for P= 4.

```val = string.Format("{0:0000}", N);
```

Step 3: Return the padded string.

Example :

## C#

 `// C# program to pad an integer ` `// number with leading zeros ` `using` `System; ` ` `  `class` `GFG{ ` `     `  `    ``// Function to pad an integer number  ` `    ``// with leading zeros ` `    ``static` `string` `pad_an_int(``int` `N, ``int` `P) ` `    ``{ ` `        ``// string used in Format() method ` `        ``string` `s = ``"{0:"``; ` `        ``for``( ``int` `i=0 ; i

Output:

```Before Padding: 123
```

Method 2: Using ToString() method : The ToString() method is used to convert the numeric value of the current instance to its equivalent string representation.

Step 1: Get the Number N and number of leading zeros P.

Step 2: Convert the number to string using the ToString() method and to pad the string use the formatted string argument “0000” for P= 4.

```val = N.ToString("0000");
```

Step 3: Return the padded string.

Example :

## C#

 `// C# program to pad an integer ` `// number with leading zeros ` `using` `System; ` ` `  `public` `class` `GFG{ ` `     `  `    ``// Function to pad an integer number  ` `    ``// with leading zeros ` `    ``static` `string` `pad_an_int(``int` `N, ``int` `P) ` `    ``{ ` `        ``// string used in ToString() method ` `        ``string` `s = ``""``; ` `        ``for``( ``int` `i=0 ; i

Output:

```Before Padding: 123
```

Method 3: Using PadLeft() method : The PadLeft() method is used to right-aligns the characters in String by padding them.

Step 1: Get the Number N and number of leading zeros P.

Step 2: Convert the number to string using the ToString() method.

```val = N.ToString();
```

```pad_str = val.PadLeft(P, '0');
```

Step 4: Return the padded string.

Example :

## C#

 `// C# program to pad an integer ` `// number with leading zeros ` `using` `System; ` ` `  `public` `class` `GFG{ ` `     `  `    ``// Function to pad an integer number  ` `    ``// with leading zeros ` `    ``static` `string` `pad_an_int(``int` `N, ``int` `P) ` `    ``{ ` `        ``// use of ToString() method ` `        ``string` `value = N.ToString(); ` `         `  `        ``// use of the PadLeft() method ` `        ``string` `pad_str = value.PadLeft(P, ``'0'``); ` `         `  `        ``// return output ` `        ``return` `pad_str; ` `    ``} ` `     `  `    ``// driver code ` `    ``public` `static` `void` `Main(``string``[] args) ` `    ``{ ` `        ``int` `N = 123; ``// Number to be pad ` `        ``int` `P = 5; ``// Number of leading zeros ` `         `  `        ``Console.WriteLine(``"Before Padding: "` `+ N); ` `         `  `        ``// Function calling ` `        ``Console.WriteLine(``"After Padding: "` `+ pad_an_int(N, P)); ` `    ``} ` `}`

Output:

```Before Padding: 123
```

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