彩票模拟编译问题

Question

I have started to write a lottery simulation program using C programming,however when i compile the program i get a compile error that i do not understand.

#include <stdio.h>

int
main(int argc, char const *argv[])
{
    //Welcome the User to the Program
        puts("============================");
        puts("         WELCOME TO         ");
        puts("============================");
        puts("  PROJECT : JACKPOT DREAMS  ");
        puts("============================");
    //Rogers 6 Original Numbers
        int nums[6] = { 5, 11, 15, 33, 42, 43 };

    //Ask how many years to simulate
        int years = 0;
        printf("How many years would you like to sleep for? :");
        scanf("%d", &years);
        printf("Ok. I will now play the lottery %d year(s)");
        printf("Sleep Tight :)....");
    //Generate Random Numbers
        int ctr;
        int randnums[6];
        srand(time(NULL));
        for( ctr = 0; ctr < 6; ctr++ ) randnums[ctr] = (rand() % 50);

    //Check Numbers with Rogerns numbers
        int win;
        for( ctr = 0; ctr < 6; ctr++ ) (randnums[ctr] == nums[ctr]) ? win = 1 : win = 0;




    return 0;
}

This is the compile error that i get:

LotteryNumbers.c:29:79: error: expression is not assignable
  ...= 0; ctr < 6; ctr++ ) (randnums[ctr] == nums[ctr]) ? win = 1 : win = 0;
                       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^
4 warnings and 1 error generated.

Answer 1

The problem is because the syntax when using the ternary operator is:

<condition> ? <true-case-code> : <false-case-code>; 

Thus in your case:

for( ctr = 0; ctr < 6; ctr++ ) win = (randnums[ctr] == nums[ctr]) ? 1 : 0;

However this doesn't that all the numbers match, it just sets win to the result of the current number being checked. To check if all the numbers match you can try:

int win = 1;
for( ctr = 0; ctr < 6; ctr++ )
{
    if(randnums[ctr] != nums[ctr])
    {
        win = 0;
        break; // if there's a mismatch we don't need to continue
    }
}

Answer 2

Change:

for( ctr = 0; ctr < 6; ctr++ ) (randnums[ctr] == nums[ctr]) ? win = 1 : win = 0;

to:

for( ctr = 0; ctr < 6; ctr++ ) win = (randnums[ctr] == nums[ctr]) ? 1 : 0;