#include<stdio.h>main(){
int a,b,c,sum;printf("please input 3 number :");scanf("%d,%d,%d",&a,&b,&c);
sum=a+b+c;printf("sum=%d\n",sum);}
// 输出结果
please input 3 number :1,2,3
sum=6
采用主函数调用子函数的方法求3个整数的和</font
#include<stdio.h>intsum(int X,int Y){
int Z;
Z=X+Y;return(Z);}main(){
int a,b,c;printf("please input 3 number :");scanf("%d,%d,%d",&a,&b,&c);
a=sum(a,b);
c=sum(a,c);printf("sum=%d\n",c);}
// 输出结果
please input 3 number :3,4,5
sum=12
3.求sum=1+2+3+……+99+100
For( ; ; )
#include<stdio.h>main(){
int i=0,sum=0;for(;i<=100;i++)
sum=i+sum;printf("i=%d,sum=%d",i,sum);}
// 输出结果
i=101,sum=5050
While()
#include<stdio.h>main(){
int i=0,sum=0;while(i<100){
i++;
sum=i+sum;}printf("i=%d,sum=%d",i,sum);}
// 输出结果
i=100,sum=5050
Do……while
#include<stdio.h>main(){
int i=0,sum=0;do{
i++;
sum=i+sum;}while(i<100);printf("i=%d,sum=%d",i,sum);}
// 输出结果
i=100,sum=5050
4.任意输入6个数,按从小到大排序输出
#include<stdio.h>#define n 6main(){
int a[n];int i,j;int temp;printf("please input 6 number:\n");for(i=0;i<=n-1;i++)scanf("%d",&a[i]);printf("\n");for(i=0;i<n-1;i++)for(j=0;j<n-1-i;j++)if(a[j]>a[j+1]){
temp=a[j];
a[j]=a[j+1];
a[j+1]=temp;}printf("输出排序后的数组:\n");for(i=0;i<=n-1;i++)printf("%d \t",a[i]);}
#include<stdio.h>main(){
int y;printf("please input a year :\n");scanf("%d",&y);if(y%100==0)if(y%400==0)printf("%d year is a leap year.\n",y);elseprintf("%d year is not a leap year.\n",y);elseif(y%4==0)printf("%d year is a leap year.\n",y);elseprintf("%d year is not a leap year.\n",y);}
// 输出结果
please input a year :20242024 year is a leap year.
6.求10!=123456789*10
#include<stdio.h>main(){
int i,a,b;printf("plese a number:");scanf("%d",&b);for(i=1,a=1;i<=b;i++)
a=a*i;printf("%d",a);}
// 输出结果
plese a number:103628800
7.任意输入一个整数n,判断该整数是否是素数
#include<stdio.h>intmain(){
int a=0;int p;int i;scanf("%d",&p);for(i=2;i<p;i++){
if(p%i==0)
a++;}if(a==0)printf("%d is a prime\n",p);elseprintf("%d is not a prime\n",p);return0;}