Contest100000568 – 《算法笔记》2.4小节——C/C++快速入门->循环结构

#include<stdio.h>
int main(){
    int n=1,sum=0;
    while(n<=100)
    {
        sum+=n;
        n++;
    }
    printf("%d",sum);
    printf("\n");
    return 0;
}

#include<stdio.h>
int main(){
    int sum=0,n=100;
    while(n!=0){
        sum=sum+n;
        n--;
    }
    printf("%d",sum);
    return 0;
}

#include<stdio.h>
int main(){
    int n=1,sum=0;
    do
    {
        sum+=n;
        n++;
    }
    while(n<=100);
    printf("%d",sum);
    printf("\n");
    return 0;
}

#include<stdio.h>
int main(){
    int sum=0;
    for(int n = 1; n <= 100; n++){
        sum+=n;
    }
    printf("%d",sum);
    printf("\n");
    return 0;
}

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

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

#include<stdio.h>
int main(){
    int sum=0;
    int N;
    for(int n = 1; sum <= 1000; n++){
        sum+=n;
        N++;
    }
    printf("%d",N);
    printf("\n");
    return 0;
}

#include<stdio.h> 
int main(){
    int sum=0,i=1;
    while(i>=1){
        if(sum<1000){
            sum=sum+i;
            i++;
        }else break;
    }
    printf("%d",i-1);
    return 0;
} 

#include<stdio.h>
int main(){
    int n;
    for(int n = 1; n <= 20; n++){
        if(n%5==0)
        {
            printf("%d",n);
        }else{
            printf("%d   ",n);
        }
        if(n%5==0){
            printf("\n");
        }
    }
    return 0;
}

#include<stdio.h>
int main(){
    int a[4][5]={1,2,3,4,5};
    for(int i=0;i<4;i++){
        for(int j=0;j<5;j++){
            if(i=1) a[i][j]=(j+1)*2;
            if(i=2) a[i][j]=(j+1)*3;
            if(i=3) a[i][j]=(j+1)*4;
        }
    }
    for(int i=0;i<4;i++){
        for(int j=0;j<5;j++){
            printf("%3d",a[i][j]);
        }
        printf("\n");
    }
    return 0;
}

#include<stdio.h>
#include<math.h>
int main(){
    double sum=0,sign=1;
    for(double i=1;fabs(1/i)>pow(10,-6);i=i+2){
        sum+=sign/i;
        sign=(-1)*sign;  //第一项为+，第二项为-，第三项为+
    }
    printf("PI=%10.8f",sum*4);
    return 0;
}

#include<stdio.h>
int main(){
    int n,i=2;
    int sum=0;
    int a[50];
    scanf("%d",&n);
    a[0]=a[1]=1;
    for(int sign=1;sign<=n;sign++){
        a[i]=a[i-1]+a[i-2];
        i++;
    }
    printf("%d",a[n-1]);
    return 0;
}

#include<stdio.h>
int main(){
    double a = 2, b = 1, temp = 0;
    double n = 0,sum = 0;
    for(int i = 0; i < 20; i++){
        n = a/b;
        sum += n;
        b = a;
        a += b;
    }
    printf("%.6f",sum);
    printf("\n");
    return 0;
}

#include<stdio.h>
int main(){
    int i=20;
    double a=2,b=1,c=0;
    double sum=0;
    while(i){
        sum=sum+a/b;
        c=b;
        b=a;
        a=b+c;
        i--;
    }
    printf("%.6f",sum);
    return 0;
}