为什么我每次都是0？？？

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
using namespace std;
char a[55],b[55],k;
float z,c;
int p,x;
int main()
{
    int i=1;
    while (1)
    {
        scanf("%c",&a[i]);
        if (a[i]=='=')
        break;
        i++;
    }
    gets(b+1);
    int al=strlen(a+1);
    int bl=strlen(b+1);
    for (int i=al-1;i>=1;)
    {
        int p=2;
        if (a[i]>='a'&&a[i]<='z')
        {
            p=1;
            k=a[i];
            i--;
        }
        int f=0;
        while (a[i]!='+'&&a[i]!='-'&&i>=1)
        {
            x=(a[i]-'0')*pow(10,f)+x;
            i--;
            f++;
        }
        if (p==1)
        {
            if (a[i]=='-')
            z=z+x;
            else
            z=z-x;
            i--;
            x=0;
        }
        if (p==2)
        {
            if (a[i]=='-')
            c=c-x;
            else
            c=c+x;
            i--;
            x=0;
        }
    }
    for (int i=bl;i>=1;)
    {
        int p=2;
        if (b[i]>='a'&&b[i]<='z')
        {
            k=b[i];
            i--;
            p=1;
        }
        int f=0;
        while (b[i]!='+'&&b[i]!='-'&&i>=1)
        {
            x=(b[i]-'0')*pow(10,f)+x;
            i--;
            f++;
        }
        if (p==1)
        {
            if (b[i]=='-')
            z=z-x;
            else
            z=z+x;
            i--;
            x=0;
        }
        if (p==2)
        {
            if (b[i]=='-')
            c=c+x;
            else
            c=c-x;
            i--;
            x=0;
        }
    }
    float ans=c/z;
    if (ans==-0)
    printf("%c=%.3f",k,0);
    else
    printf("%c=%.3f",k,ans);
    return 0;
}