如果了解分数运算，本题很简单。我有对分数知识进行总结

分数四则运算

#include<stdio.h>

#include<algorithm>

using namespace std;

int gongyue(int a,int b){

    return !b?a:gongyue(b,a%b);

}

struct fenshu{

    int fenzi;

    int fenmu;

}shu1,shu2,shu3;

bool fenshujudge(struct fenshu A,struct fenshu B){//返回A是否大于B

    return (double)A.fenzi/A.fenmu>(double)B.fenzi/B.fenmu;

}

int main(){

    shu3.fenzi=0;

    int flag=0;

    scanf("%d/%d",&shu1.fenzi,&shu1.fenmu);

    scanf("%d/%d",&shu2.fenzi,&shu2.fenmu);

    if(fenshujudge(shu1,shu2)){

        int a=shu1.fenzi,b=shu1.fenmu;

        shu1.fenzi=shu2.fenzi;shu1.fenmu=shu2.fenmu;

        shu2.fenzi=a;shu2.fenmu=b;

    }

    scanf("%d",&shu3.fenmu);

    for(int i=0;i<shu3.fenmu;i++){

        shu3.fenzi++;

        //shu3大于shu1，小于shu2

        if(fenshujudge(shu3,shu1)&&fenshujudge(shu2,shu3)&&gongyue(shu3.fenmu,shu3.fenzi)==1){

            if(flag==0)

            {printf("%d/%d",shu3.fenzi,shu3.fenmu);flag=1;continue;}

            printf(" %d/%d",shu3.fenzi,shu3.fenmu);

        }

    }

    return  0;

}