Question

代码模拟两个模具的滚动36000次，并输出“和= _；频率= _；百分比= _”。编译后的代码可以正确输出除百分比以外的所有内容。当应输出“（frequency [calcCount] / 36000）* 100”的商时为“百分比= 0”，这是数据类型冲突吗？如何正确输出商？

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define SUM_SIZE 36000
#define FREQUENCY_SIZE 13

int main(void){
    int rollCount; // counter to loop through 36000 rolls of dice & sums
    int calcCount; //counter to loop through frequencies 1-12 of sum calculation

//initialize frequency counters to 0
int frequency[FREQUENCY_SIZE] = {0};

//calculation array
int calculation[SUM_SIZE];

//seed
srand((unsigned)(time(NULL)));

for (rollCount = 1; rollCount <= SUM_SIZE; rollCount++){
    //rolling first die
    int face1 = (1 + ( rand() % 6));
    //rolling second die
    int face2 = (1 + ( rand() % 6));
    int sum = face1 + face2;
    //initializing array elements
    calculation[rollCount] = sum;
    //for each roll, select value of an element of array calculation
    //and use that value as subscript in array frequency to determine
    //element to increment (which in this case is the sum frequency)
    ++frequency[calculation[rollCount]];
}

//displaying results
for (calcCount = 2; calcCount < FREQUENCY_SIZE; calcCount++){
    //calculating percentage
    int percentage = (frequency[calcCount] /36000) * 100;
    printf("Sum = %d; Frequency = %d; Percentage = %d \n", calcCount, frequency[calcCount], percentage);
}

}

Answer 1

当您在两个整数之间进行除法时，结果也将是整数，并且“精确”结果将被截断以适合整数。例子：

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以及您做什么时

3/2 -> 1
10/3 -> 3
5/10 -> 0

部分int percentage = (frequency[calcCount] /36000) * 100;首先被计算。它是两个frequency[calcCount] /36000之间的除法，由于int小于frequency[calcCount]，因此结果为零。因此，乘以100仍为零。

相反，首先要做乘法-

另一种替代方法是使用浮点，如：

int percentage = (100 * frequency[calcCount]) /36000;

但是您需要将打印更改为使用％f

double percentage = (frequency[calcCount] /36000.0) * 100;
                                                ^^^
                               Notice the .0 to make 36000 a double

输出数组和整数的商时出错

1 个答案: