对于c中的for循环内的循环

Question

出于某种原因,我的外部for循环似乎没有做任何事情,我检查了所有的paranthesis,一切看起来还不错,但它仍然没有循环.有了这个程序,我想总计50个随机数(数字可以是1或-1 ......这是计算物理问题)并打印程序所做的大小.但我想进一步做10次,并计算平均幅度.我知道我需要做什么我只是遇到了这个循环的问题.

#include<stdio.h>
#include<math.h>
#include<stdlib.h>
#include<time.h> //Neeed this to seed the random generator with time, or else it      will always generate the same numbers.

//This is a program to calculate the magnitude of the displacement of a particle after    random collisions.
#define RAND_MAX 1
int main()
{   
    //using ints because the particle can only move one unit on x-axis at a time.
    int i, x, displacement, sum = 0, avg;
    int total_disp=0, mag_disp;
    srand(time(NULL));


    //Each collision causes the particle to advance or retreat by one unit on the x axis.

    for(i=0; i<10; i++)
    {   
        for (i=0; i<50; i++)    //for 50 collisions
        {

            x = rand() % 2;  //generates random numbers between 0 and 1.
            if (x==0)   //if x is 0 then it was a displacement in the minus x direction
            {
                displacement = -1;
            }
            else {  //if x is 1 it is a displacement in the minus x direction
                displacement = 1;
            }
            printf("the disp is : %d\n", displacement);
            total_disp = total_disp + displacement;     //sum the displacements

        }

        if (total_disp < 0) {
            mag_disp = total_disp * -1;
        }

        else{ mag_disp = total_disp; }

        printf("The total displacement is: %d\n", mag_disp);
        sum = sum + mag_disp;   //sum of the displacement magnitudes, there should be ten of them in this case
        avg = sum / i; //average displacement is the sum of all the magnitudes divded by the number of times this is performed.
        printf("The average displacement for i = %d particles is: %d", i, avg);
    }
    return 0;
}

Answer 1

您不能在两个循环中使用相同的迭代变量.

for(i=0; i<10; i++)
    for (i=0; i<50; i++)

递增i到50在外部循环的第一次迭代.

for(i=0; i<10; i++)
    for (j=0; j<50; j++)

将工作.

Answer 2

你在i两个循环中使用相同的变量.你应该使用不同的变量.

...
for(j=0; j<10; j++)
{    
   for (i=0; i<50; i++)    //for 50 collisions
   {
    ...