5-3-example

CH5.3.c

//
//  main.c
//  CH5.3 - Example
//  P85 - strlenn: return length of string s
//

#include<stdio.h>
int strlenn(char *m);

int main(void)
{
    char test[20] = "hello world";  //correct, this char stores an integer, which equals to the address of the tesst[0]
    //printf("please input the test string:");
    //scanf("%s", test);
    
    //char test2 = "hello world";   //incorrect, char is a small integer, cannot be assigned by an array char[12]
    //correct version of test 2
    char *test2;
    test2 = "hello world";
    
    printf("the length of string \"hello world\"is :%d\n", strlenn(test));
    printf("the length of string - 1 \"hello world\"is :%d\n", strlenn(test+1));
    printf("the length of string - 2 \"hello world\"is :%d\n", strlenn(&test[2]));
    printf("the length of string \"hello world\"is :%d\n", strlenn(test2));
    printf("the length of string \"hello'\\0' world\"is :%d\n", strlenn("hello'\0' world"));

    return 0;
}

int strlenn(char *s)
{
    int n;
    for (n = 0; *s != '\0'; s++) {
        n++;
    }
    return n;
}

the length of string "hello world"is :11
the length of string - 1 "hello world"is :10
the length of string - 2 "hello world"is :9
the length of string "hello'\0' world"is :6
Program ended with exit code: 0