c语言循环结构

填空题

声明：答案仅供参考，出现问题自行承担。
由于网站渲染问题，答案中的’==‘与’<‘进行了转义，所以答案可能有错，比如多个’\‘，又或者少’=='。

实验3

整数分离并输出

scanf(“%d”,&a)
a!=0
a%10
printf(“%d\n”,r)
a/10

拉赞助

0
0
count++;sum>=2000
break

红绿蓝球

red=1
green=0
8-red-green
blue>=0 && blue<=6

韩信点兵

i<100
i%3==2 && i%5==3 && i%7==2

合成数据

(ch=getchar())
ch>=‘0’ && ch<=‘9’
ch - ‘0’
y*10 + x

亲密数

i%j==0
a+=j
\j<a
a%j==0
b==i

统计各类字符个数

letters=0, digits=0, spaces=0, others=0
(ch=getchar()) !=‘\n’;(ch>=‘A’&&ch<=‘Z’) || (ch>=‘a’&&ch<=‘z’)
ch>=‘0’&&ch<=‘9’
ch == ’ ’

求自然数1至n（n>1）的累加和

s=0
i=1
i<=n
i++
s+=i

输出每个月的天数

(month)
((year%4==0 && year%100!=0) || (year%400==0))
day = 28
break;
case1:case3:case5:case7:case8:case10:case12
case 4: case 6: case 9: case 11:

计算阶乘之和

1
i<=n
f*i
sum+f

求1+12+123+12…n（n位数）的值

t = ’ ’
i <= n
t = t * 10 + i

完全数

scanf(“%d”, &n)
n%i == 0
s+i
s == n

求最大公约数

“%d%d”,&m,&n
m%n
n=r
r!=0
“%d\n”,m

穷举法求最大公约数

(a<b?a:b)
a%i==0&&b%i==0
break

求Sn=a+aa+aaa—aa(n个a)的值

tn = tn + a
tn = tn * 10

训练3

求最大公约数

“%d%d”,&m,&n
m%n
n=r
r!=0
“%d\n”,m

计算阶乘之和

1
i<=n
f*i
sum+f

整数分离并输出

scanf(“%d”,&a)
a!=0
a%10
printf(“%d\n”,r)
a/10

拉赞助

0
0
count++
sum>=2000
break

完全数

scanf(“%d”, &n)
n%i == 0
s+i
s == n

穷举法求最大公约数

(a<b?a:b)
a%i==0&&b%i==0
break

红绿蓝球

red=1
green=0
8-red-green
blue>=0 && blue<=6

韩信点兵

i<=100
i%3==2 && i%5==3 && i%7==2

合成数据

(ch=getchar())
ch>=‘0’ && ch<=‘9’
ch - ‘0’
y*10 + x

亲密数

i%j==0
a+=j
j<a
a%j==0
b==i

统计各类字符个数

letters=0, digits=0, spaces=0, others=0
(ch=getchar()) !=‘\n’
(ch>=‘A’&&ch<=‘Z’) || (ch>=‘a’&&ch<=‘z’)
ch>=‘0’&&ch<=‘9’
ch == ’ ’

求自然数1至n（n>1）的累加和

s=0
i=1
i<=n
i++
s+=i

输出每个月的天数

(month)
((year%4==0 && year%100!=0) || (year%400==0))
day = 28
break;
case1:case3:case5:case7:case8:case10:case12
case 4: case 6: case 9: case 11:

求1+12+123+12…n（n位数）的值

t = ’ ’
i <= n
t = t * 10 + i

求Sn=a+aa+aaa—aa(n个a)的值

tn = tn + a
tn = tn * 10

编程题

声明：答案仅供参考，出现问题自行承担。

循环实验

求1到n之间的奇数之和

#include <stdio.h>
int main() {
    int n, sum = 0;
    scanf("%d", &n);
    for (int i = 1; i <= n; i += 2) {
        sum += i;
    }
    printf("%d", sum);
}

计算n的阶乘

#include<stdio.h>
int main(){
    int n,i,s=1;
    scanf("%d",&n);
    for(i=1;i<=n;i++)
        s=s*i;
    printf("%d\n",s)}

求总金额

#include<stdio.h>
int main(){
    float i,v,m=0;
    int n;
    scanf("%d",&n);
    for(i=1;i<=n;i++){
        scanf("%f",&v);
        m+=v;
    }
    printf("%.2f",m);
}

整数的位数

#include<stdio.h>
int main()
{
    unsigned int n,i=0;
    scanf("%d",&n);
    while (n){
        i++;
        n/=10;
    }
    printf("%d",i);
}

求数列前n项之和

#include<stdio.h>
int main()
{
    unsigned int n,i;
    double s=0;
    scanf("%d",&n);
    for (i=1;i<=n;i++)
    {
        s+=1.0/(2*i-1);
}
    printf("%.2lf",s);
}

输出直角三角形

#include<stdio.h>
int main(){
    char ch;
    int n,i,j;
    scanf("%c%d", &ch, &n);
    for (i = 0; i < n; i++)
    {
        for (j = 0; j <= i; j++)
            printf("%c", ch);
        printf("\n");
    }
}

判断素数

#include<stdio.h>
int main()
{
    int i = 2,a;
    scanf("%d", &a);
    while (i < a){
        if (a % i == 0){
            i++;
            break;
        }
        else i++;
    }
    if (i == a)
        printf("1\n");
    else printf("0\n");
}

求阶乘的和

#include<stdio.h>
int main(){
    int n,c = 1,i,m,s = 0,he = 0;
    scanf("%d%d", &m, &n);
    for (i = m; i < n + 1; i++)
    {
        c *= i;
        s = c;
        he += s;
    }
    printf("%d", he);
}

输出某闭区间中的素数

#include<stdio.h>
int main(){

    int a,b,i,k,j;
    scanf("%d %d",&a,&b);
    for(i=a;i<=b;i++){
        k=0;
        for(j=2;j<=i/2;j++){
            if(i%j==0 && i>2){
                k=1;
                break;
            }
        }
        if(k==0){
            printf("%d,",i);
        }
    }
}

求一组数据的平均值

#include<stdio.h>
int main(void)
{
    int n = 0;
    double average = 0;
    double num;//
    double sum = 0;
    while (scanf("%lf", &num) != EOF)
    {
        sum += num;
        n++;
    }
    average = sum / n;
    printf("%.2lf\n", average);
}

统计字母个数

#include<stdio.h>
int main(){
    char a[1000];
    gets(a);
    int sum=0,i=0;
    while(a[i]!='@'){
        if((a[i]>='a'&&a[i]<='z')||(a[i]>='A'&&a[i]<='Z')){
            sum++;
        }
        i++;
    }
    printf("%d",sum);
}

输出图形

#include<stdio.h>
int main()
{
    int i, j, n, k;
    scanf("%d", &n);
    for (i = 0; i < n; i++)
    {
        for (j = 0, k = i + 1; j <= i; k += (i + 1), j++)
            printf(j == i ? "%-6d\n" : "%-6d", k);
    }
}

一行字符变换

#include<stdio.h>
int main()
{
    char c;
    while ((c = getchar()) != EOF && c != '\n')
    {
        if (c >= 'a' && c <= 'z')
            printf("%c", c - 32);
        else if (c >= 'A' && c <= 'Z')
            printf("%c", c + 32);
        else printf("%c", c);
    }
}

输出闭区间内的素数

#include <stdio.h>
#include <stdbool.h>
bool is_prime(int num);
int main() {
    int m, n;
    scanf("%d %d", &m, &n);
    if (m > n) {
        int temp = m;
        m = n;
        n = temp;
    }
    bool first = true;
    for (int i = m; i <= n; i++) {
        if (is_prime(i)) {
            if (!first) {
                printf("");
            }
            printf("%d ", i);
            first = false;
        }
    }
}
bool is_prime(int num) {
    if (num <= 1) {
        return false;
    }
    for (int i = 2; i * i <= num; i++) {
        if (num % i == 0) {
            return false;
        }
    }
    return true;
}

分数统计

#include<stdio.h>
int main() {
    int n, a = 0, b = 0, c = 0, d = 0, e = 0;
    double f;
    scanf("%d", &n);
    for (int i = 0; i < n; i++) {
        scanf("%lf", &f);
        if (f <= 100.0 && f >= 90.0) {
            a++;
        } else if (f < 90.0 && f >= 80.0) {
            b++;
        } else if (f < 80.0 && f >= 70.0) {
            c++;
        } else if (f < 70.0 && f >= 60.0) {
            d++;
        } else if (f < 60.0 && f >= 0.0) {
            e++;
        }
    }
    printf("A:%d\n", a);
    printf("B:%d\n", b);
    printf("C:%d\n", c);
    printf("D:%d\n", d);
    printf("E:%d\n", e);
}

循环训练

求1到n之间的奇数之和

#include <stdio.h>
int main()
{
    int i,n,m=0;
    scanf("%d",&n);
    for (i=1;i<=n;i++){
        if (i%2==1){
            m+=i;
        }
    }
    printf("%d",m);
    return 0;
}

统计字母个数

#include<stdio.h>
int main(){
    char a[1000];
    gets(a);
    int sum=0,i=0;
    while(a[i]!='@'){
        if((a[i]>='a'&&a[i]<='z')||(a[i]>='A'&&a[i]<='Z')){
            sum++;
        }
        i++;
    }
    printf("%d",sum);
}

输出图形

#include<stdio.h>
int main()
{
    int i, j, n, k;
    scanf("%d", &n);
    for (i = 0; i < n; i++)
    {
        for (j = 0, k = i + 1; j <= i; k += (i + 1), j++)
            printf(j == i ? "%-6d\n" : "%-6d", k);
    }
}

一行字符变换

#include<stdio.h>
int main()
{
    char c;
    while ((c = getchar()) != EOF && c != '\n')
    {
        if (c >= 'a' && c <= 'z')
            printf("%c", c - 32);
        else if (c >= 'A' && c <= 'Z')
            printf("%c", c + 32);
        else printf("%c", c);
    }
}

输出闭区间内的素数

#include <stdio.h>
#include <stdbool.h>
bool is_prime(int num);
int main() {
    int m, n;
    scanf("%d %d", &m, &n);
    if (m > n) {
        int temp = m;
        m = n;
        n = temp;
    }
    bool first = true;
    for (int i = m; i <= n; i++) {
        if (is_prime(i)) {
            if (!first) {
                printf("");
            }
            printf("%d ", i);
            first = false;
        }
    }
}
bool is_prime(int num) {
    if (num <= 1) {
        return false;
    }
    for (int i = 2; i * i <= num; i++) {
        if (num % i == 0) {
            return false;
        }
    }
    return true;
}

分数统计

#include<stdio.h>
int main() {
    int n, a = 0, b = 0, c = 0, d = 0, e = 0;
    double f;
    scanf("%d", &n);
    for (int i = 0; i < n; i++) {
        scanf("%lf", &f);
        if (f <= 100.0 && f >= 90.0) {
            a++;
        } else if (f < 90.0 && f >= 80.0) {
            b++;
        } else if (f < 80.0 && f >= 70.0) {
            c++;
        } else if (f < 70.0 && f >= 60.0) {
            d++;
        } else if (f < 60.0 && f >= 0.0) {
            e++;
        }
    }
    printf("A:%d\n", a);
    printf("B:%d\n", b);
    printf("C:%d\n", c);
    printf("D:%d\n", d);
    printf("E:%d\n", e);
}

求组合数

#include<stdio.h>
double fact(int n)
{
    double sum1 = 1;
    for(int x=1;x<=n;x++)
    {
        sum1 = sum1*x;
    }
    return sum1;
}
int main()
{
    int m,n;
    double result;
    scanf("%d %d",&m,&n);
    result = fact(n)/(fact(m)*fact(n-m));

    printf("result = %.0f",result);
    return 0;
}

统计字符

#include<stdio.h>
int main ()
{
    int digit,letter,other,blank;
    char ch;
    int i;
    digit=letter=other=blank=0;
    for(i=1;i<=10;i++)
    {
        ch=getchar();
        if((ch>='a'&&ch<='z')||(ch>='A'&&ch<='Z'))
            letter++;
        else if(ch>='0'&&ch<='9')
            digit++;
        else if(ch==' '|| ch=='\n')
            blank++;
        else other++;
    }
    printf("letter = %d, blank = %d, digit = %d, other = %d",letter,blank,digit,other);
    return 0;
}

计算n的阶乘

#include<stdio.h>
int main(){
    int n,i,s=1;
    scanf("%d",&n);
    for(i=1;i<=n;i++)
        s=s*i;
    printf("%d\n",s);
}

求e的近似值

#include<stdio.h>
int main()
{
    int m;
    double s=1,y=1;
    scanf("%d",&m);
    for(int j=1;j<=m;j++)
    {
        s=1;
        for(int i=1;i<=j;i++)
        {
            s=s*i;
        }
        y=y+1.0/s;
    }
    printf("%.8f",y);
    return 0;
}

最大公约数和最小公倍数

#include <stdio.h>
#include <math.h>
int main(){
    int m,n;
    scanf("%d %d",&m,&n);
    int yushu;
    yushu=m%n;
    int  x;
    x=m*n;
    if(yushu==0){
        printf("%d %d",n,x/n);
    }else{
        while(yushu!=0){
            m=n;
            n=yushu;
            yushu=m%n;
        }
        printf("%d %d",n,x/n);
    }
    return 0;
}

打印菱形图案

#include<stdio.h>
int main()
{
    int n,i,j,k;
    scanf("%d",&n);
    k=n/2;
    for(j=1;j<=k+1;j++)
    {
        for(i=1;i<=j+k;i++)
        {
            if(i<=k+j&&i>k-j+1)
                printf("* ");
            else printf("  ");
        }
        printf("\n");
    }
    for(j=k+2;j<=n;j++)
    {
        for(i=n;i>j-k-1;i--)
        {
            if(i<=n-j+k+1&&i>j-k-1)
                printf("* ");
            else printf("  ");
        }
        printf("\n");
    }
}

猴子吃桃问题

#include <stdio.h>
int main() {
    int N;
    scanf("%d", &N);
    int peaches = 1;
    for (int day = N - 1; day > 0; day--) {
        peaches = (peaches + 1) * 2;
    }
    printf("%d\n", peaches);
    return 0;
}

兔子繁衍问题

#include <stdio.h>
int fx(int target) {
    if (target == 1) {
        return 1;
    }
    int a = 1, b = 1, c;
    int index = 2;
    while (1) {
        c = a + b;
        index++;
        if (c >= target) {
            return index;
        }
        a = b;
        b = c;
    }
}
int main() {
    int n;
    scanf("%d", &n);
    printf("%d", fx(n));
    return 0;
}

打印九九口诀表

#include <stdio.h>
int main() {
    int N;
    scanf("%d", &N);
    for (int i = 1; i <= N; i++) {
        for (int j = 1; j <= i; j++) {
            printf("%d*%d=%-4d", j, i, j * i);
        }
        printf("\n");
    }
    return 0;
}

奇偶分家

#include <stdio.h>
int main() {
    int N;
    scanf("%d", &N);
    int num, odd = 0, even = 0;
    for (int i = 0; i < N; i++) {
        scanf("%d", &num);
        if (num % 2 == 1) {
            odd++;
        } else {
            even++;
        }
    }
    printf("%d %d\n", odd, even);
    return 0;
}

求1到N的和

#include <stdio.h>
int main() {
    int N;
    scanf("%d", &N);
    int sum = N * (N + 1) / 2;
    printf("sum = %d\n", sum);
    return 0;
}

求简单交错序列前N项和

#include <stdio.h>
int main() {
    int N;
    scanf("%d", &N);
    double sum = 0.0;
    int sign = 1;
    for (int i = 1; i <= N; i++) {
        double term = sign * 1.0 / (3 * i - 2);
        sum += term;
        sign *= -1;
    }
    printf("sum = %.3f\n", sum);
    return 0;
}

求总金额

#include<stdio.h>
int main(){
    float i,v,m=0;
    int n;
    scanf("%d",&n);
    for(i=1;i<=n;i++){
        scanf("%f",&v);
        m+=v;
    }
    printf("%.2f",m);
}

求幂之和

#include <stdio.h>
#include <math.h>
int main() {
    int n;
    scanf("%d", &n);
    int sum = 0;
    for (int i = 1; i <= n; i++) {
        sum += pow(2, i);
    }
    printf("result = %d\n", sum);
    return 0;
}

整数的位数

#include<stdio.h>
int main()
{
    unsigned int n,i=0;
    scanf("%d",&n);
    while (n){
        i++;
        n/=10;
    }
    printf("%d",i);
    return 0;
}

求数列前n项之和

#include<stdio.h>
int main()
{
    unsigned int n,i;
    double s=0;
    scanf("%d",&n);
    for (i=1;i<=n;i++)
    {
        s+=1.0/(2*i-1);
    }
    printf("%.2lf",s);
}

输出直角三角形

#include<stdio.h>
int main(){
    char ch;
    int n,i,j;
    scanf("%c%d",&ch,&n);
    for (i=0;i<n;i++)
    {
        for (j=0;j<=i;j++)
            printf("%c",ch);
        printf("\n");
    }
    return 0;
}

判断素数

#include<stdio.h>
int main()
{
    int i=2,a;
    scanf("%d",&a);
    while(i<a){
        if (a%i==0){
            i++;
            break;
        }
        else i++;
    }
    if (i==a)
        printf("1\n");
    else printf("0\n");
    return 0;
}

求阶乘的和

#include<stdio.h>
int main(){
    int n,c=1,i,m,s=0,he=0;
    scanf("%d%d",&m,&n);
    for(i=m;i<n+1;i++)
    {
        c*=i;
        s=c;
        he+=s;
    }
    printf("%d",he);
    return 0;
}