android下的数学工具，其中含有质数计算器，-android under the mathematical tools, which contains a prime number calculator,

素数为只能被自己和1整除的数.如果i j等于0,说明i不是素数,跳 出本层循环-prime number can only be yourself and divisible if i j is equal to 0, indicating that i is not prime, jumped out of the loop