I'm a real beginner. I'm trying to create an array of integers to represent a very large number (three digits of the number per element of the array). I'll start out by reading two large numbers as strings from a file, and converting each of them to an integer array. Then I need to perform addition, subtraction, and multiplication on these two arrays, and store the results in a third array. Then, I'll convert the resulting integer array back into a string and output it.

The sizes of the arrays and the segment of code used to add the numbers (below) were given to me by my professor. He also gave us the basic idea for converting to/from a string/integer array, but I'm quite sure I haven't executed it correctly. Here's what I've got so far, just for the addition operation:

Does this look remotely close at all?Code:void main() { int i, ca, length1, length2, length3, t; char s1[20], s2[20], s3[20]; //s1, s2 are read from file, s3 will be printed result int a[16], b[16], c[16]; //used in performing arithmetic operations FILE *ff; ff = fopen("a.txt", "r"); fscanf(ff, "%s", s1); //1st large number fscanf(ff, "%s", s2); //2nd large number length1 = strlen(s1); length2 = strlen(s2); //CONVERTS LARGE NUMBER STRINGS TO INT ARRAYS for(i = 0; i < 16; i++){ a[i] = (s1[length1 - (3 * i + 3)] - 48)*100 + (s1[length1 - (3 * i + 2)] - 48)*10 + (s1[length1 - (3 * i + 1)] - 48); b[i] = (s2[length2 - (3 * i + 3)] - 48)*100 + (s2[length2 - (3 * i + 2)] - 48)*10 + (s2[length2 - (3 * i + 1)] - 48); } //TO ADD THE TWO ARRAYS for(i = 0; i < 22; i++){ //adds c[1] = a[i] + b[i]; } for(i = 0; i < 21; i++){ //rectifies carry-over from addition ca = c[i] / 10; c[i] = c[i] % 10; c[i + 1] = c[i + 1] + ca; } //CHANGE RESULTING INT ARRAY INTO A STRING for(i = 0; i < 16; i++){ s3[i] = c[3 * i] % 10 + 48; c[3 * i] = c[3 * i] / 10; } length3 = strlen(s3); //REVERSES STRING for(i = 0; i < length3 / 2; i++){ t = s3[i]; s3[i] = s3[length3 - i - 1]; s3[length3 - i - 1] = t; } //PRINTS RESULT FROM ADDITION printf("The sum is %s \n", s3); fclose(ff); }