GFG App
Open App
Browser
Continue

# C program to find the length of a string

Given a string str. The task is to find the length of the string.

Examples

```Input: str = "Geeks"
Output: Length of Str is : 5

Input: str = "GeeksforGeeks"
Output: Length of Str is : 13```

In the below program, to find the length of the string str, first the string is taken as input from the user using scanf in , and then the length of Str is calculated using and using method .
Below is the C program to find the length of the string.

Example 1: Using loop to calculate the length of string.

## C

 `// C program to find the length of string ` `#include ` `#include ` ` `  `int` `main() ` `{ ` `    ``char` `Str[1000]; ` `    ``int` `i; ` ` `  `    ``printf``(``"Enter the String: "``); ` `    ``scanf``(``"%s"``, Str); ` ` `  `    ``for` `(i = 0; Str[i] != ``'\0'``; ++i); ` ` `  `    ``printf``(``"Length of Str is %d"``, i); ` ` `  `    ``return` `0; ` `} `

Output

`Enter the String: Length of Str is 0`

Time Complexity: O(N)
Auxiliary Space: O(1)

Example 2: Using strlen() to find the length of the string.

## C

 `// C program to find the length of  ` `// string using strlen function ` `#include ` `#include ` ` `  `int` `main() ` `{ ` `    ``char` `Str[1000]; ` `    ``int` `i; ` ` `  `    ``printf``(``"Enter the String: "``); ` `    ``scanf``(``"%s"``, Str); ` ` `  `    ``printf``(``"Length of Str is %ld"``, ``strlen``(Str)); ` ` `  `    ``return` `0; ` `} `

Output

`Enter the String: Length of Str is 0`

Time Complexity: O(1)
Auxiliary Space: O(1)

Example 3: Using sizeof() to find the length of the string.

## C

 `// C program to find the length of ` `// string using sizeof() function ` `#include ` `#include ` ` `  `int` `main() ` `{ ` ` `  `    ``printf``(``"Enter the String: "``); ` ` `  `    ``char` `ss[] = ``"geeks"``; ` ` `  `    ``printf``(``"%s\n"``, ss); ` ` `  `    ``// print size after removing null char. ` `    ``printf``(``"Length of Str is %ld"``, ``sizeof``(ss) - 1); ` ` `  `    ``return` `0; ` `} ` `// This code is contributed by ksam24000`

Output

```Enter the String: geeks
Length of Str is 5```

Time Complexity: O(1)
Auxiliary Space: O(1)

My Personal Notes arrow_drop_up