C String Exercises

string_exercises.c

//Ex.4 - Write a function that reads a line of any length from a file and
//returns it as a string.

#include <stdio.h>
#include <stdlib.h>

/*
 * Counts the length of NUL terminated
 * character array.
 */
int dstrlen(char *string){
    int count = 0;
    while(string[count]) {
        count++;
    }
    return count;
}


char* dstrcpy(char *dst, const char *src){
    int count = 0;

    while (src[count]){
        dst[count] = src[count];
        count++;
    }
    dst[count] = src[count];

    return dst;
}


char* dstrcat(char *dst, char *src){
    int concat_index = dstrlen(dst);
    dstrcpy(&dst[concat_index], src);
    return dst;
}

/*
 */
char* stringadd(char *a, char *b){
    int new_length = (dstrlen(a) + dstrlen(b) + 1);
    char *new_string = malloc(sizeof(char) * new_length);
    dstrcpy(new_string, a);
    dstrcat(new_string, b);
    return new_string;
} 

int main(int argc, char **argv) {
    char first[] = "dragan";
    char last[] = "marjanovic";


    char *new_string;
    printf("First: %s, Last: %s, New:%s\n",first,last,new_string);
    new_string = stringadd(first, last);
    printf("First: %s, Last: %s, New:%s\n",first,last,new_string);


    free(new_string);
    return 0;
}