Converting the values from array to ascii? - c++

Question

#include<stdio.h>
#define msize 4096
struct memory
{
int a[msize];
};
void read(struct memory *m)
{
int i;
for(i=0;i<sizeof(msize);i++)
{
scanf("%d",&m->a[i]);
}
}
int main()
{
struct memory m;
m.a[0]=250; // temperature value of 25,0
m.a[4]=01; // heater status OFF
m.a[8]=240; // temperature value of 24,0
m.a[12]=00; // heater status ON
m.a[16]=220; // temperature value of 22,0
m.a[20]=00; // heater status ON
read(&m);
return 0;
}
I have created a structure of a particular memory size and inserted some values to the array and reading those values from the array. I have a difficulty to convert this value to ASCII.

Answer 1

In for(i=0;i<sizeof(msize);i++), it will not be i<4096,rather it will compare i to the size of an integer on your platform.In 32-bit systems,it will be 4.So the loop will exit after just 4 iterations.
Further in your function, &m->a[i] will be m->a[i] as m is a pointer.
PS There is something very wrong with the logic of your program.You are assigning some values to the array elements in main(),but are overwriting the same in the function read().
As for converting integer values from an array to ASCII, it's fairly simple.You just have to use the %c format specifier and pass the array elements are arguments.But I must point out there aren't 450 ASCII values to print.Since a character only has one byte,the max you can manage with it is 256 characters.
PS Many of the ASCII characters you want to print are not print-able.One is whose ASCII value equals 0.

Answer 2

My suggestion is inputting by character if you want to store in ASCII.
like this
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#define msize 4096
struct memory {
char a[msize];
};
/*
m.a[0]=250; // temperature value of 25,0
m.a[4]=01; // heater status OFF
m.a[8]=240; // temperature value of 24,0
m.a[12]=00; // heater status ON
m.a[16]=220;// temperature value of 22,0
m.a[20]=00; // heater status ON
*/
int read(struct memory *m){
char inputbuff[4+1];
int i=0;
memset(m->a, ' ', sizeof(m->a)/sizeof(m->a[0]));//initialize by space
while(i<msize/(4+4)){
printf("input temperature value e.g.25,0 : 250(and enter)\n");
fgets(inputbuff, sizeof(inputbuff), stdin);
strncpy(m->a + i*4, inputbuff, 3);
//i+=1;
printf("input heater status ON or OFF e.g.ON : 00 , OFF : 01(and enter)\n");
fgets(inputbuff, sizeof(inputbuff), stdin);
strncpy(m->a + (i+1)*4, inputbuff, 2);
i += 1;
printf("continue input? (y or n) : ");
fgets(inputbuff, sizeof(inputbuff), stdin);
if(*inputbuff=='n' || *inputbuff=='N'){
break;
}
}
return i;
}
int main(void){
struct memory m;
read(&m);
{
//check print
m.a[msize-1]='\0';
printf("%s\n", m.a);
}
return 0;
}
ADD for more
#include <stdio.h>
#include <string.h>
#define msize 4098
int *storeInt(void *address){
int *ip =(int*)address;
*ip = 777;//ip[0]=777;ip[1]=888;...
return ip;
}
char *storeChars(void *address){
char *cp =(char*)address;
strcpy(cp, "hello");
return cp;
}
void dump(void *address, size_t length){
unsigned char *cp = (unsigned char*)address;
size_t i;
for(i=0;i<length;++i){
if(i % 16 == 0) printf("\n");
printf("%02X ", *cp++);
}
}
int main(void){
static char memory[msize];//create a static memory of a particular size
char *block1, *block2;
block1 = &memory[0];
block2 = &memory[1024*2];//split a virtual
int *ip;
ip=storeInt(block1);//store some values in the memory
printf("%d\n", *ip);//read the values from the memory
char *cp;
cp=storeChars(block2);//set hello\0
printf("%s\n", cp);//say hello
char ascValue[12];
int value = *ip;//777
//convert "value of int" to Ascii
sprintf(ascValue, "%d", value);
//Display it
printf("value is %s\n", ascValue);
dump(block1, 8);
dump(block2, 8);
return 0;
}

Answer 3

If your read() function is intended to read from memory and print to a terminal then you should be using printf() instead of scanf(). printf() will convert integer values to ASCII through the %d format string. scanf() reads from the standard input and stores to memory. scanf() converts from ASCII to integer through the %d format string.