C language 1 day a small program 2, C language small program

C language 1 day a small program 2, C language small program

Program functions:

Enter an integer to print all the prime numbers within this integer.

Program example:

# Include <stdio. h>
# Include <stdlib. h>
# Include <math. h>

Bool IsPrime (int x)
{
Bool bResult = false;

Int I, k;
K = (int) sqrt (x );

For (I = 2; I <= k; I ++)
{
If (x % I = 0)
{
Break;
}
}

If (I> k)
{
BResult = true;
}
Else
{
BResult = false;
}

Return bResult;
}

Int main ()
{
Int a = 0;
Int B = 0;
Int I = 0;
Printf ("enter an integer :");
Scanf ("% d", & );

For (I = 3; I <= a; I ++)
{
If (IsPrime (I ))
{
Printf ("% d \ n", I );
}
}

System ("pause ");
Return 0;
}

Program parsing:

1. The IsPrime () function is used to determine whether an integer is a prime number. If yes, true is returned. Otherwise, false is returned. Because the C language library function sqrt () is called in this function, # include must be included in the header file.

2. The scanf_s () function is used to obtain user input data and save the data to a local variable.

Summary:

1. the math. h header file declares some common mathematical operations, such as multiplication and open operations. If you want to use functions in the C standard library, you need to include the header file of the function.

2. We can use the scanf () function to obtain data from the terminal.