printing a 2d array of string in c - c

Question

i'm trying to print a 2d array of string as practice(i'm a newbie) with no success i've tried every combination i could think of still nothing i'm sure i'm doing a silly error somewhere i just can't see it here some of the example:
using a pointer :
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define lim 10
#define maxx 25
void print(char *);
int main()
{
int i = 1;
char input[lim][maxx];
char *ps = input;
printf("type the list of %d names or type quit to leave \n", lim);
while (i<lim && gets(input[i]) != NULL && strncmp(input[i], "quit", 4)!=0 ) {
i++;
}
printf("i've counted %d names\n", i);
print("\n");
print(ps);
return 0;
}
void print(char *a)
{
int i=0;
printf("the list of names include : \n");
while(*(a) != '\0') {
printf("%s\n", *(a+i));
i++;
}
}
here's the output:
type a list of %d names or type quit to leave :
bla
bli
blo
quit
i've counted 4 names
the list of names include :
segmentation fault (core duped)
another version of the print function is like this :
void print(char aray[lim][maxx])
{
int i,j;
printf("the list of names include : \n");
for(i = 0; i < lim; i++) {
for(j = 0; j < maxx; j++){
puts(aray[i][j]);
//printf("%s\n", aray[i][j]);
}
}
}
i get the same output, can anyone help me debug this ? and thx in advance

Answer 1

In short, it looks like you need to brush up on your pointers. With your original print function:
void print(char *a)
{
int i=0;
printf("the list of names include : \n");
while(*(a) != '\0') {
printf("%s\n", *(a+i));
i++;
}
}
You are printing the value at a + i every iteration. This might sound like what you want, but what you actually pass to print is a pointer to an array of arrays of char (your compiler should be throwing a warning about incompatible pointer types). That is, the "proper" type of ps is (char *)[]. So in the print function you are only advancing the memory address by sizeof(char) with each iteration, whereas what you actually want is to increment it by sizeof(char) * maxx (the size of your array entries). To implement this change, do the following:
change declaration of print
void print(char (*)[maxx]);
change to proper pointer type
char (*ps)[maxx] = input;
And finally, change print function to something like:
void print(char (*a)[maxx]){
printf("the list of names include : \n");
int i;
for (i = 0; i < lim; i++){
printf("%s\n",*a);
a++;
}
}
You need not use the (a+i) syntax, as just advancing a by one each iteration accomplishes the same thing, and is possibly faster for large i. And of course, as others have mentioned, double check your new line printing, I believe you want printf('\n').

Answer 2

You are adding i as 1 which will not help in case of your two dimensional array as the next element will be at maxx location,so you can do something like this
//here lim and max are defined in your program
void print(char *a){
int i=0;
printf("the list of names include : \n");
while(i<(lim*maxx)){
printf("%s\n",a );
i += maxx;
a = a + maxx;
}
}
and the second variant should be
void print(char aray[lim][maxx])
{
int i,j;
printf("the list of names include : \n");
for(i = 0; i < lim; i++) {
cout<<aray[i]<<"\n";
}
}

Answer 3

You start on index 1 in your 2d array, you should start with index 0
int i=1;
Your print function takes an array of characters and then does a printf string of each character which makes no sense
void print(char *a)
{
int i=0;
printf("the list of names include : \n");
while(*(a)!='\0')
{
printf("%s\n",*(a+i));
i++;
}
}
instead make it look like this
void print(char *a[], int strings)
{
int i = 0;
for (; i < strings; ++i)
{
puts( a[i] );
}
}
and call it with the number of strings you read
print(ps,i);
You would also be better off using fgets() instead of gets(), especially since your strings are max 25 chars so its easy to give a longer string. fgets() lets you specify the max size of the string fgets(input[i],maxx,stdin)
Your other function
void print(char aray[lim][maxx])
{
int i,j;
printf("the list of names include : \n");
for(i = 0; i < lim; i++) {
for(j = 0; j < maxx; j++){
puts(aray[i][j]);
//printf("%s\n", aray[i][j]);
}
}
}
does a similar wrong assumption about the level of indirection
arra[i][j] is one character but puts takes a string argument, so puts( arra[i][j] ); is not correct, you could try fputc( arra[i][j], stdout ) instead since fputc takes one character

Answer 4

fix to
void print(char (*)[maxx]);
int main()
{
int i = 0;//int i = 1;
char input[lim][maxx] = { {'\0'}};
char (*ps)[maxx] = input;
printf("type the list of %d names or type quit to leave \n", lim);
while (i<lim && gets(input[i]) != NULL && strncmp(input[i], "quit", 4)!=0 ) {
i++;
}
printf("i've counted %d names\n", i);
printf("\n");//print("\n");
print(ps);
return 0;
}
void print(char (*a)[maxx])
{
int i=0;
printf("the list of names include : \n");
while(i<lim && a[i][0] != '\0') {
printf("%s\n", a[i]);
i++;
}
}