Thread: Need help with strings and arrays

Need help with this:

1. Write a function that takes in a string and returns an array which contains the index of all the spaces in the string.
For example, "This is an example" should return "5 8 11", which are the numbers of the space characters.
It should also return the total number of spaces.

2. Write a function that takes in a string and a character matrix. The function fills in the character matrix so that each line of the character matrix is an individual word in the string.
So "This is an example" should be sent to the character matrix as:

This
is
an
example

Here is what I have come up with, but I am stuck.

Code:

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




int spaceTest(char x[], int out[])
{
    int count=0, i; //use count for total number of spaces
    for(i=0; i<15;i++)
    {
        if(x[i]=' ')
        {
            out[i]=i;
            count++;
        }
    }
    return count;
}




void fillCharMatrix(char x[], char matrix[][1])
{
    int i, count=1;
    for(i=0;i<4;i++)
    {
        while(x[i] != ' ')
        {
            matrix[count][1]=matrix[count][1]+x[i];//really not sure how to do this part
        }
        count++;
    }
}


int main()
{
    char x[100]="This is an example";
    int out[100];
    int total= spaceTest(x,out);
    printf("Index of all the spaces\n");
    printf("%d\n",out);
    printf("Total number of spaces is %d\n",total);
    char matrix[100][1];
    fillCharMatrix(x,matrix);
    printf("The character matrix is:\n");
    printf("%c\n", matrix);
    return 0;
}

So far the program runs fine, but nothing prints out correctly, but I just cant figure out what to change.
Im really just stuck inside the two loops, please let me know how I can get the problem working correctly. Thanks for the help!

In spaceTest() you should have out[count]=i; instead of out[i]=i;
In main you forgot to print out the 'out' array. I haven't looked at the 2nd part of the problem yet.

Good catch! That's why I always put the constant literal first, as in if (' ' == x[i]) so that any similar errors of assignment get caught immediately.

Great, my number of spaces printed out right, but the index still isn't printing out "5 8 11" and the character matrix isn't working.

In fact, now the program stalls after it prints out the number of spaces, can anyone help me with the issue?

I can't make heads or tails out of your code, above, but getting 5 8 11 is easy.

Code:

int x[100]={"This is an example"};
int out[100]={0};
int countOfSpaces=0;
int i, j;

for(i=0;x[i];i++) {
   if(x[i] == ' ')
      out[i] = 1;
}

for(int j=0;j<i;j++) {
   if(out[j]) {
       printf("%d ", j );
      countOfSpaces++;
   }
}
printf("\n\nThere were %d spaces",countOfSpaces);

Study that logic, and see what you think.

Ok, I got my first function working

Now I have this for my second function

Code:

void fillCharMatrix(char x[], char matrix[][100])
{
    int i, count=1;
    for(i=1;i<18;i++)
    {
        matrix[count][i]=x[i];
        if(x[i] == ' ')
        {
            count++;
        }
    }
}

What should I change here to correctly display the matrix as

This
is
an
example

if(x[i]=' ')
= -> ==

Walk through the letters in the string of char's. See if the letter you're looking at is a space. If it is, then print a newline char, instead of the space.

Study this assignment long and hard, because I assure you that a lot of string problems are solved using this basic "walk through the letters, testing each one", technique.