#include<stdio.h>
void main()
{
    void trans(float n);
    float n;
    scanf("%f",&n);
    int p;
    p=(int)n;   //为啥这里不能把float转化为int类型的，该怎么改？我这个程序想把输入转化为英语。小数点后面程序不用！！就是求助这里为啥不能转化！！！//
    trans(p);
}
void trans(int n)
{
    int t[10],i=0,j,m,p;
    char a[][15]={"","One ","Two ","Three ","Four ","Five ","Six ","Seven ","Eight ","Nine ","Ten ","eleven ","Twelve ","Thirteen ","Fourteen ","Fifteen ","Sixteen ","Seventeen ","Eighteen ","Nineteen "};
    char b[][15]={"","","Twenty ","Thirty ","Forty ","Fifty ","Sixty ","Seventy ","Eighty ","Ninety ","hundred "};
    char c[][10]={"","thousand ","million ","billion "};
    while(n>0)
    {
        t[i]=n%1000;
        n=n/1000;
        i++;
    }
    if(n==1000000000)
        printf("%s%s",a[1],c[3]);
    for(j=i-1;j>=0;j--)
    {
        if(t[j]>=100)
        {
            m=t[j]/100;
            t[j]=t[j]%100;
            printf("%s%sand",a[m],b[10]);
        }
        if(t[j]>=20)
        {
            m=t[j]/10;
            t[j]=t[j]%10;
            printf("%s",b[m]);
        }
        if(t[j]>0)
            printf("%s",a[t[j]]);
        if(j>0)
        {
            printf("%s",c[j]);
        }
    }
    printf("\n");
}

第一次调用函数的时候,n没有值，再一个，
while(n>0)
     {
         t[i]=n%1000;
         n=n/1000;
         i++;
     }
这段控制循环条件有问题，因为你如果输入的大于0，则死循环！！
 

float p；写在前面
#include<stdio.h>
void main()
{
    void trans(float n);
    float n;
    float p;
    scanf("%f",&n);
    p=(int)n;   //为啥这里不能把float转化为int类型的，该怎么改？我这个程序想把输入转化为英语。小数点后面程序不用！！就是求助这里为啥不能转化！！！//
    trans(p);
}
void trans(int n)
{
    int t[10],i=0,j,m,p;
    char a[][15]={"","One ","Two ","Three ","Four ","Five ","Six ","Seven ","Eight ","Nine ","Ten ","eleven ","Twelve ","Thirteen ","Fourteen ","Fifteen ","Sixteen ","Seventeen ","Eighteen ","Nineteen "};
    char b[][15]={"","","Twenty ","Thirty ","Forty ","Fifty ","Sixty ","Seventy ","Eighty ","Ninety ","hundred "};
    char c[][10]={"","thousand ","million ","billion "};
    while(n>0)
    {
        t[i]=n%1000;
        n=n/1000;
        i++;
    }
    if(n==1000000000)
        printf("%s%s",a[1],c[3]);
    for(j=i-1;j>=0;j--)
    {
        if(t[j]>=100)
        {
            m=t[j]/100;
            t[j]=t[j]%100;
            printf("%s%sand",a[m],b[10]);
        }
        if(t[j]>=20)
        {
            m=t[j]/10;
            t[j]=t[j]%10;
            printf("%s",b[m]);
        }
        if(t[j]>0)
            printf("%s",a[t[j]]);
        if(j>0)
        {
            printf("%s",c[j]);
        }
    }
    printf("\n");
}
ok了！