Question

1. Write a C or C++ program A8p1.c(pp) that accepts one command line string parameter. Call the fork function to produce two processes. In the child process print out the lower case version of the string. In the parent process print out the reversed upper case version of the string (e.g. child: “abc”; parent: ”CBA”). You may call the toupper and tolower functions in the header <ctype.h> if you wish. Specify in the output whether the parent or child process is printing. Submit code source file, not screen shots.

Answer 1

#include <stdio.h>
#include <sys/types.h> 
#include <unistd.h>
#include <ctype.h>  


void printLower(char *s) {
        int i = 0;
        while(s[i] != '\0') {
                printf("%c", tolower(s[i++]));
        }
        printf("\n");
}

void printUpperRev(char *s) {
        if(s[0] == '\0') {
                return;
        }
        printUpperRev(s + 1);
        printf("%c", toupper(s[0]));
}

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

        if(argc < 2) {
                printf("Error! enter a command line parameter.\n");
                return 0;
        }

        int pid = fork();

        if(pid == 0) {
                // child process
                
                printf("In child process: ");
                printLower(argv[1]);

        } else {
                
                printf("In parent process: ");
                printUpperRev(argv[1]);
        printf("\n");
        }
}

Please upvote, as i have given the exact answer as asked in question. Still in case of any issues in code, let me know in comments. Thanks!