how to print an array of 2 dimensions using pointers

Question

How can I print the other elements in the array using pointers? I can do it with the first element of the array which the pointer is pointing to but I am confused in doing it with two dimensional arrays.

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

void getInfo(char* pID, int* pHP);
void dispInfo(char* pID, int* pHP);

int main()
{
//declarations   
    char ID[100][15] = {""}; //char* pID[100];
    char* pID = &ID[0][0];
    int HP[100] = {0};
    int* pHP = &HP[0];
    int answer = 0;
    int Ecount = 0;//keep count of engines input/processed

//input    
    do {
        getInfo(pID + Ecount, pHP + Ecount);
        Ecount++;
        printf("More? 1 for yes 0 for no: ");
        scanf("%d", &answer);
    }while(answer != 0);

//output
    dispInfo(pID, pHP);

    return 0;
}

void getInfo(char* pID, int* pHP)
{
    printf("Enter engine ID: ");
    scanf("%s", pID);
    printf("Enter engine HP: ");
    scanf("%d", pHP);
}//end getInfo

void dispInfo(char* pID, int* pHP)
{
    printf("Engine ID: %s\n", pID);
    printf("Engine HP: %d\n", *pHP);
}//end dispInfo

Khaled.K · Accepted Answer · 2015-03-26 05:42:51Z

Notes

int main()
{  
    char ID[100][15] = {""};
    char* pID = &ID[0][0];
    int HP[100] = {0};
    int* pHP = &HP[0];

    ..

    dispInfo(pID, pHP);

    return 0;
}

void dispInfo(char* pID, int* pHP)
{
    printf("Engine ID: %s\n", pID);
    printf("Engine HP: %d\n", *pHP);
}

char * pID should be char ** pID to traverse over the matrix
To print all of the array content inside the function dispInfo you need to pass size of the array

Solution

int main()
{
    const int SIZE = 100;

    char ID[SIZE][15] = { "" };
    char ** pID = &ID[0];

    int HP[SIZE] = { 0 };
    int * pHP = &HP[0];

    ..

    dispInfo(pID, pHP, SIZE);

    return 0;
}

void dispInfo(char ** pID, int * pHP, const int SIZE)
{
    for (int i=0; i<SIZE; i++)
    {
        printf("Engine ID: %s\n", *(pID+i));
        printf("Engine HP: %d\n", *(pHP+i));
    }
}

Chintan Patel · Accepted Answer · 2015-03-26 05:24:16Z

0

in your program, pID and pHP will be pointing to the last inputs entered by you so don't use pID and pHP to print data. You are maintaining number of inputs entered in Ecount variable, use it to print data like below.

for(int i=0;i<Ecount;i++)
{
    dispInfo(ID[i],&HP[i]);
}

edited Mar 26, 2015 at 5:24

answered Mar 26, 2015 at 5:18

Chintan Patel

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