# std::strspn

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< cpp‎ | string‎ | byte

Defined in header `<cstring>` |  |
size_t strspn( const char* dest, const char* src ); |  |

Returns the length of the maximum initial segment (span) of the byte string pointed to by `dest`, that consists of only the characters found in byte string pointed to by `src`.

### Parameters

dest | - | pointer to the null-terminated byte string to be analyzed
src | - | pointer to the null-terminated byte string that contains the characters to search for

### Return value

The length of the maximum initial segment that contains only characters from byte string pointed to by `src`

### Example

Run this code

    #include <cstring>
    #include <string>
    #include <iostream>

    const char *low_alpha = "qwertyuiopasdfghjklzxcvbnm";
    int main()
    {
        std::string s = "abcde312$#@";

        std::size_t spnsz = std::strspn(s.c_str(), low_alpha);
        std::cout << "After skipping initial lowercase letters from '" << s
                  << "'\nThe remainder is '" << s.substr(spnsz) << "'\n";
    }

Output:

    After skipping initial lowercase letters from 'abcde312$#@'
    The remainder is '312$#@'

### See also

strcspn | returns the length of the maximum initial segment that consists of only the characters not found in another byte string (function)
wcsspn | returns the length of the maximum initial segment that consists of only the wide characters found in another wide string (function)
strpbrk | finds the first location of any character from a set of separators (function)
C documentation for strspn

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