作业二分支，循环结构

//计算和差积商余数
#include<stdio.h>
int main(void)
{
int num1,num2;
double y;
char op;
printf("type in an expression:");
scanf("%d%c%d",&num1,&op,&num2);
printf("%d%c%d",num1,op,num2);

if(op=='+'){
y=num1+num2;
printf("=%.2f\n",y);
}
else if(op=='-'){
y=num1-num2;
printf("=%.2f\n",y);
}
else if(op=='*'){
y=num1*num2;
printf("=%.2f\n",y);
}
else if(op=='/'){
y=(num1/num2);
printf("=%.2f\n",y);
}
else if(op=='%'){
y=num1%num2;
printf("=%.2f\n",y);
}
else{
printf("unknown operator\n");
}

return 0;
}

//不调用pow函数求幂
#include<stdio.h>
int main(void)
{
int i,n;
double x,y;
printf("enter n:");
scanf("%d",&n);
printf("enter x:");
scanf("%lf",&x);
y=1;

for(i=1;i<=n;i++){

y=y*x;
}

printf("y=%.3f\n",y);

return 0;
}

//计算函数
#include<stdio.h>
int main(void)
{
int m,n;
double s,i;
printf("m:");
scanf("%d",&m);
printf("n:");
scanf("%d",&n);
s=0;

for(i=m;i<=n;i++){

s=s+i*i+(1/i);
}
printf("s=%.2f\n",s);

return 0;
}

//计算数列
#include<stdio.h>
int main()
{
int n,m;
double s,i;
printf("enter n:");
scanf("%d",&n);
s=0;
m=1;
for(i=1;i<=n;i++){
s=s+m*(i/(2*i-1));
m=(-1)*m;
}
printf("s=%.3f\n",s);

return 0;
}

//调用pow函数求幂
#include<stdio.h>
#include<math.h>
int main()
{
int m,n,i;
printf("enter n:");
scanf("%d",&n);
m=0;

for(i=1;i<=n;i++){
m=m+pow(2,i);
}
printf("m=%d\n",m);

return 0;
}

//计算贷款问题
#include<stdio.h>
#include<math.h>
int main()
{
int year,money,loan;
double rate,month,x,y;
printf("enter loan:");
scanf("%d",&loan);
printf("enter rate:");
scanf("%lf",&rate);

for(year=5;year<=30;year++){
month=year*12;
x=rate*pow((1+rate),month);
y=pow((1+rate),month)-1;
money=loan*(x/y);
printf("year=%d",year);
printf("money=%d\n",money);
}

return 0;
}