Comparing two arrays..in c-CodePudding

I set up two arrays one of 50 units big, array1[50] which has 50 random integers from a range of 50-100 and another array which prompts the user to enter in 10 intgers from the same range of numbers. My problem is, how do i compare the two, im tyring to find the number of times the 10 user inputted numbers match the numbers stored in the array1[50] which holds the seedeed random numbers. Ive tried to do a for loop within a for loop, like this.

array2[10]
array[50]
int counter = 0;

for(int i = 0; i < 10;   i){
    for(int k = 0; k < 50;   k){  //i've tried this and it does not work, i don't know what else to do
        if( array2[i] == array[k]);
          counter;
    }
}
//any help is appreciated thanks.

CodePudding user response：

There are easier ways to achieve this using other libraries. But considering you're working with small arrays, you could use your code with the following modification:

array2[10]
array[50]
int counter = 0;

for(int i = 0; i < 10;   i){
for(int k = 0; k < 50;   k){  
if( array2[i] == array[k])counter  ;
}
}

That should work.

CodePudding user response：

As pointed out @yano & @Weather Vane a semicolon at the end of if( array2[i] == array[k]); makes it a separate statement. As a result counter is incremented every time and ends up with value 500.

Instead of comparing each element of input with all random value you can just prepare a master table for storing random values as indexes. This way, you only check number of times the user inputs.

Since the range is just [50..100], it can be done using array of size 101. For larger range say more than a million, 1000000 use dynamic memory (malloc() siblings).

To populate the random values you can use :

    #define RANGE_MIN 50
    #define RANGE_MAX 100
    #define RAND_NUM_COUNT 50

    srand (time(NULL));

    char master [RANGE_MAX   1] = {0};
    for (int ri = 0; ri < RAND_NUM_COUNT; ) {
        int xnum = RANGE_MIN   rand() % (RANGE_MAX - RANGE_MIN   1);
        if (master [xnum]) continue;
        master[xnum] = 1;
          ri;
    }

To count how many times user has guessed numbers right:

    int input[guesses];
    int ans = 0;
    for (int ui = 0; ui < guesses;   ui) {
        if (input[ui] < RANGE_MIN || input[ui] > RANGE_MAX)
            continue;
        if (master[input[ui]]) // correct guess / match
              ans;
    }
    printf ("User has guessed %d correctly out of %d guesses.\n", ans, guesses);

What if the user repeats his guesses, i.e. you want to count unique guesses only. You can reset a correct guess in master[] so that repetition is not counted.

    for (int ui = 0; ui < guesses;   ui) {
        if (input[ui] < RANGE_MIN || input[ui] > RANGE_MAX)
            continue;
        if (master[input[ui]]) {    // correct guess / match
              ans;
            master[input[ui]] = 0;  // next repeat is not counted
        }
    }