问题1:
#include <stdio.h>
#include <math.h>
bool IsPrime(int iNum)
{
bool bPrime = false;
int iSqrt = (int)sqrt(iNum);
for (int i=2; i<=sqrt(iNum); i++)
{
if (iNum % i == 0){
break;
}
}
if (i > iSqrt){
bPrime = true;
}
return bPrime;
}
int main()
{
// Question 1
int iPrimeCount=1;
int iRow=0;
for (int i=1; i<=100; i++)
{
if (iPrimeCount>20){
break;
}
if (IsPrime(i)){
iRow++;
iPrimeCount++;
printf("%d\t", i);
}
if (iRow==5){
printf("\n");
iRow = 0;
}
}
printf("\n");
return 0;
}
问题2:
#include <stdio.h>
int main()
{
printf("Please Input two numbers: ");
int a=0,b=0;
scanf("%d%d", &a, &b);
if (a > b){
a = a^b;
b = a^b;
a = a^b;
}
int iSum = 0;
for (int k=a; k<=b; k++)
{
iSum += k;
}
printf("%d\n", iSum);
return 0;
}
问题3:(应该是打印乘法口诀吧)
#include <stdio.h>
int main()
{
for (int j=1; j<=9; j++)
{
for (int m=1; m<=j;m++)
{
printf("%d\t", j*m);
}
printf("\n");
}
return 0;
}