I= 1。 In mathematical calculation, for the convenience of calculation, 1 is assigned to I, thus simplifying the calculation. This assignment phenomenon often occurs in mathematics. In C language, I is equal to 1, which belongs to giving an initial value and performing variable loop operation. For example: i= 1, i=i++, the value of one period is 2, and the value of two periods is 3. That is, after one cycle, the value of I is 2, assign 2 to I, and execute the second cycle until 3.