Question

Write a program in C to generate random numbers. The program recieves 4 items on activation through argv:

1. Name of the data file

2. Number of items for program to generate

3. Range of numbers

4. Seed of the random number generator

Example run: ./rand datafile.txt 20 1000 3127

Program must convert all numbers to ints using atoi(), must save all parameters into variables, opens the data file to write the random numbers into it, program loops to generate the number of items, all numbers are generated by rand() call initiated by seed and are limited using range and modular division, all generated numbers are saved in datafile.txt, and finally the program must read the file by printing all numbers separated by a tab in rows of 10 until the end of the file.

Only use raw I/O interaction with appropriate buffers. Only use printf, fgets, scanf, read/write system calls (no cin/cout). Also check that argc takes the correct amount of parameters (5 counting rand executable).

Answer 1

If you have any doubts, please give me comment...

#include<stdio.h>

#include<string.h>

#include<stdlib.h>

int main(int argc, char *argv[]){

if(argc!=5){

printf("USAGE: ./rand <out-filename> <no-of-items> <range> <seed>\n");

return 0;

}

char filename[100];

strcpy(filename, argv[1]);

int n = atoi(argv[2]);

int range = atoi(argv[3]);

int seed = atoi(argv[4]);

srand(seed);

FILE *fp;

fp = fopen(filename, "w");

for(int i=0; i<n; i++){

fprintf(fp, "%d\n", rand()%range);

}

fclose(fp);

printf("Successfully stored into file\n");

fp = fopen(filename, "r");

int i=0, num;

printf("File contents in file is: \n");

while(!feof(fp)){

if(fscanf(fp, "%d", &num)<0)

break;

printf("%d\t", num);

i++;

if(i%10==0)

printf("\n");

}

printf("\n");

return 0;

}