Question

在这段代码中，你键入一个数字，然后通过返回0或1告诉你它是否为素数。然后它应该打印数组'prime'的0或1项。但是，我遇到了这个问题，我不知道如何解决列表问题。（我对C来说是全新的）

#include <stdio.h>
#include <string.h>
int test(int number) { /*1 means prime, 0 means not*/
    int iter;
    int mod;
    if (number == 1) {
        return 0;
    }
    for (iter=2;iter<number-1;iter+=1) {
        if (number % iter == 0){
            return 0;
        }
    }
    return 1;
}
int main(){
    char prime[2] = {'This number isn\'t prime','This number is prime'};
    int userIn;
    printf("Enter an integer to check: ");
    scanf("%d",userIn);
    printf("%c",prime[test(userIn)]);
}

Answer 1

我添加了函数声明和printf。

#include <stdio.h>

int primeNumber(int number); //function declaration

int main() {
    int userIn;
    printf("Enter an integer to check: ");
    scanf("%d",&userIn);
    if(primeNumber(userIn) == 0) {
        printf("This number isn\'t prime");
    } else {
        printf("This number is prime");
    }
    return 0;
}

int primeNumber(int number) {
    int iter;
    if (number == 1 || number < 0) {
        return 0;
    }
    for (iter = 2; iter < number - 1; iter += 1) {
        if (number % iter == 0){
            return 0;
        }
    }
    return 1;

}

Answer 2

bool IsPrime (int number) { // Make your function names more descriptive...
    int iter;
    // int mod; ...and remove superfluous variables

    if (number < 1) {
        return false;
    }

    // There are further possibilities for improvement here...
    for (iter = 2; iter < number - 1; iter += 1) {
        if (number % iter == 0) {
            return false;
        }
    }

    return true;
}

int main(int argc, char *argv[])
{
    const char* outcomes[2] = { "This number isn't prime", "This number is prime" };
    int input;
    printf("Enter an integer to check: ");
    scanf("%d", &input);   // Note that scanf requires pointer to input! 
    printf("%s", outcomes[IsPrime(input)]);

    return 0;
}

在C中，你可以在数组中使用字符串，如果没有，是否有解决方法

2 个答案: