C char and string

An easy exercise to get in touch with C char and strings handling

Write
void show( const char s[])
which prints the ascii values of the first ten chars in s.

Write a function
int mylen( const char * s)
which returns the useful length of the string s. C strings are terminated by a zero char.
Please do not use strlen from the string.h library, but write it with raw C. [1]

Test this with several examples, including the null string "".

Use your function as part of a program to count the number of 4 letter words typed to it. The central part is
char buff[100];
while (scanf(" %s", buff) != EOF){
// do something with buff, which should hold
// a zero-terminated string.
}
a.out expects you to type words to it, followed by an end of file (CTRL-D).

Try
cat /usr/dict/words | a.out

SOLUTION


#include <stdio.h>
void show(const char s[]){
         int i = 0;
          while(i<10){
                    printf("%d\n",s[i]);
                    i++;
          }
}

int mylen( const char * s){
          int cont = 0;
          while(s[cont]!='\0'){
                    cont++;
          }
          return cont;
}

int countFourLettersWords(){
          char buff[100];
          int cont = 0;
          while(scanf("%s",buff)!= EOF){
                    if(mylen(buff)==4)
                              cont++;
          }
          return cont;
}

int main(){
          char s[]="Hello world";
          char empty[]="";
          char num[]="01234";
          show(s);
          printf("Length:\n %d\n",mylen(s));
          show(empty);
          printf("Length:\n %d\n",mylen(empty));
          show(num);
          printf("Length:\n %d\n",mylen(num));
          printf("I will count the four letters words:\n");
          printf("%d \n",countFourLettersWords());
          getchar();
}

Exercise from: CS3008