如何将“ for”用于变量和不同的数字？

Question

I want to create a for like this:

for(int i=-0.8;i<2;i+n){
...
}

I do have the error: error: not a statement.

Whats my mistake? Can I do it like this?

Thanks for help.

-Regards

ChrizZly

Answer 1

for(int i=-0.8;i<2;i+n){

Here, i+n is not valid. You need to assign the new value to i , so it should be like this

for(int i=-0.8;i<2;i=i+n){

or

for(int i=-0.8;i<2;i+=n){

You also need to modify the type of i to double , as int doesnt have decimals.

for(double i=-0.8;i<2;i+=n){

Answer 2

int i=-0.8;

0.8 is a double value. Should not be assigned to int

for(int i=0;i<2;i++)//to increment i by one
or

for(int i=0;i<2;i+=n)//increment i by n

you can search for compound operators in java.

If you want to use double in loop, for the stopping condition you can use

for(double i = 0.0 ; Double.compare(i, n) > 0 ; i+=n)

Double.compare(d1, d2)   // is more precise for comparing double/float values

• returns the value 0 if d1 is numerically equal to d2
• a value less than 0 if d1 is numerically less than d2
• a value greater than 0 if d1 is numerically greater than d2

Answer 3

You are assigning a double value to an int . This is invalid. Use:

double i = -0.8

You are not modifying the counter variable ( i ) in the step section. i+n is a mathematical operation, not an assignment. Use:

i += n

The condition is OK

Final for loop:

for (double i = -0.8; i < 2; i += n){
    //...
}

Answer 4

First problem:

int i=-0.8 (Type mismatch: cannot convert from double to int)

Second problem:

in order to have a correct for statement you have to use an assignment where you wrote i+n

This is a possible compiling snippet of code

    double n=10.0;
    for(double i=-0.8; i<2.0 ;i=i+n){
        ....    
    }

Answer 5

make it int i = 0; or double = -0.8; int i = -0.8 will be error because 0.8 is not integer. it double. I hope you will get this.