What are the methods of obtaining string length in C language
This article mainly introduces the relevant knowledge of the method of obtaining string length in C language, the content is detailed and easy to understand, the operation is simple and fast, and has a certain reference value. I believe you will gain something after reading this article on the method of obtaining string length in C language. Let's take a look.
First, use the sizeof () operator
In C language, sizeof () is the operator of length, and you can put data types or expressions in parentheses, which we usually use to calculate the length of a string.
Basic usage:
Int iTunes 10 str sizeof (I); / / expression char str [] = "hello world"; sizeof (str); sizeof (double); / / data type
When using sizeof () to calculate the length of a string,'"is also calculated into the length of the string. For example," abcd "calculates the length with sizeof () to get 5.
Note: char str [100] = ""; the value of sizeof (str) is 100.
Second, use strlen function
Functions for calculating the length of strings are provided in string.h.
Syntax:
Size_t strlen (const char * str)
When using the strlen function, you need to add a string.h header file, which calculates the length of the string and does not include'".
Third, write functions
If you don't want to use sizeof () and strlen (), you can use a loop to determine the length of the string.
Int get_length (char str []) {char * p = str; int count = 0; while (* paired +! = ") {count++;} return count;}
This function returns a length numeric value by passing in a string.
Test the code:
# include # include int get_length (char str []) {char * p = str; int count = 0; while (* paired +! = ") {count++;} return count;} int main () {char str [] =" abcd "; int count1 = sizeof (str); int count2 = strlen (str); int count3 = get_length (str) Printf ("use sizeof the length is d", count1); printf ("use strlen the length is d", count2); printf ("use get_length the length is d", count3); return 0;}
Results:
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