How to convert an integer array to a string without the use of a library [closed]

问题

So I am working on an internship project.

I have to develop a whole system that will gather some data and will then send it through to a server. The system consist of an MSP430G2553 microcontroller so I am coding in pure C without any library's, so no sprintf or malloc functions I can use.

The problem that I am having at the moment is that I have no idea how I am going to send all the data that is in an array to the server at once.

I have the array ADCvalue[20] with 20 values, ranging from 0-350

ADCvalue[20]= {10, 40, 50, 90, 100, 200, 300, 240, 260, 10, 40, 50, 90, 100, 200, 300, 240, 260, 300, 20}.

Now I want to send these values all at once with the delimiter "," between every value to the server. Like this:

10,40,50,90,100,200,300,240,260,10,40,50,90,100,200,300,240,260,300,20

How can I get the array like this and send it through at once? I already have a print function that can send for example: char property[] = "property" as a string.

It would be great if somebody could help me with some psuedo code or some algorithmes to get me started.

回答1:

As you stated not to use any library (for whatever reason), I just wrote a simple writeIntValue-function. See the following code which uses this function to write a sequence of positive integral values into a character array. Hope it helps.

char* writeIntValue(int val, char* dest) {
    // count digits:
    int digits = 0;
    int valCopy = val;
    while (valCopy) {
        digits++;
        valCopy /= 10;
    }

    if (digits == 0)  // means val has been 0
        digits=1; // assume 1 digit to write the '0'-value

    for (int i=digits-1; i>=0; i--) {
        dest[i] = val%10 + '0';
        val/=10;
    }
    dest[digits] = '\0'; // write string-terminating 0x0-value
    return dest + digits; // return a pointer to the end of the value written so far
}

int main() {

    int ADCvalue[20]= {10, 40, 50, 90, 100, 200, 300, 240, 260, 10, 40, 50, 90, 100, 200, 300, 240, 260, 300, 20};

    char buffer[500] = { '\0' };
    char *dest = buffer;
    for (int i=0; i<20; i++) {
        if (i>0)
            *dest++ = ',';
        dest = writeIntValue(ADCvalue[i], dest);
    }
    // buffer here will be "10,40,50,90,100,200,300,240,260,10,40,50,90,100,200,300,240,260,300,20"
    return 0;
}

回答2:

Try this code

const char ansitable[10] = {'0','1','2','3','4','5','6','7','8','9'};

void procInt(char* buf, int* loc, unsigned short v) {
   if (v == 0) {
      buf[*loc] = '0';
      *loc++; 
      return; 
   }
   unsigned short cv = v;
   unsigned short r;
   unsigned short divid = 1;  
   if (v>9) divid = 10;  
   if (v>99) divid = 100;  
   while (divid > 0) {
      r = cv / divid;
      buf[*loc] = ansitable[r];
      *loc++; 
      cv %= divid;
      divid /= 10;
   }
}

int MAX_SIZE_OF_CHUNCK = 4;

void startWrite(unsigned short* input, int sizeinput) {
   char* buffer = (char *)calloc(sizeinput * MAX_SIZE_OF_CHUNCK, sizeof(char));
   int loc = 0;
   for (int i = 0; i < sizeinput; i++) {
      procInt(buffer, &loc, input[i]);
      if (i < sizeinput-1) {
         buffer[loc] = ',';
         loc++;
      }
   }
   sendToMPU(buffer, loc); //loc - length 
}

回答3:

How can I get the array like this and send it through at once? I already have a print function that can send for example: char property[] = "property" as a string.

Values in the range [0 ... 350] doesn't fit in a single byte, but you can encode those values using pairs of bytes.

An example

short int x = 300; /* 0x012C */

unsigned char arr[] = {0x01, 0x2C};

short int x[] = {0x000a, 0x0028, 0x0032, 0x005a, 0x0064, 0x00c8, 0x012c, 0x00f0, 0x0104, 0x000a, 0x0028, 0x0032, 0x005a, 0x0064, 0x00c8, 0x012c, 0x00f0, 0x0104, 0x012c, 0x0014};

unsigned char arr[] = {0x00, 0x0a, 0x00, 0x28, 0x00, 0x32, 0x00, 0x5a, 0x00, 0x64, 0x00, 0xc8, 0x01, 0x2c, 0x00, 0xf0, 0x01, 0x04, 0x00, 0x0a, 0x00, 0x28, 0x00, 0x32, 0x00, 0x5a, 0x00, 0x64, 0x00, 0xc8, 0x01, 0x2c, 0x00, 0xf0, 0x01, 0x04, 0x01, 0x2c, 0x00, 0x14};

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

int main(void)
{
    short int ADCvalue[] = {10, 40, 50, 90, 100, 200, 300, 240, 260, 10, 40, 50, 90, 100, 200, 300, 240, 260, 300, 20};
    size_t sz = sizeof(ADCvalue) / sizeof(*ADCvalue);
    unsigned char *arr = malloc(sz * 2);

    if (arr == NULL) {
        perror("malloc");
        exit(EXIT_FAILURE);
    }
    /* Encode */
    for (size_t i = 0; i < sz; i++) {
        arr[i * 2 + 0] = (unsigned char)(ADCvalue[i] >> 8);
        arr[i * 2 + 1] = (unsigned char)(ADCvalue[i] & 0xFF);
    }
    /* Send array */
    /* .. */
    /* Decode */
    for (size_t i = 0; i < sz; i++) {
        printf("%d\n", (arr[i * 2] << 8) | (arr[i * 2 + 1]));
    }
    return 0;
}

来源：https://stackoverflow.com/questions/43853141/how-to-convert-an-integer-array-to-a-string-without-the-use-of-a-library

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arrays

microcontroller