#include<stdio.h>

double expo(int a, int b)
{
    int i,aux;
    double ex=1;
    
    if(b<0)
        aux=-b;
    else
        aux=b;  

    for(i=1;i<=aux;i++)
        ex=ex*a;
    if(b>=0)    
        return (ex);
    else
        return (1/ex);
}
        

double atof(char s[])
{
    double val,pot,ex;
    int i,sinal,sig=1,nc;
    
    for(i=0;s[i]==' '||s[i]=='\n'||s[i]=='\t';i++)
    ;
    sinal=1;
    if(s[i]=='+'||s[i]=='-')
        sinal=(s[i++]=='+')?1:-1;
        
    for(val=0;s[i]>='0'&&s[i]<='9';i++)
        val=10*val+s[i]-'0';
    if(s[i]=='.')
        i++;
          
    for(pot=1;s[i]>='0'&&s[i]<='9';i++){
        val=10*val+s[i]-'0';
        pot*=10;
    }
    
    ex=1;
    if(s[i]=='e'||s[i]=='E')
    {
        i++;
        if(s[i]=='+'||s[i]=='-')
        {
                sinal=(s[i]=='+')?1:-1;
                i++;
        }    
        for(nc=0;s[i]>='0'&&s[i]<='9';i++)
            nc=(10*nc+s[i]-'0')*sinal;
                
        ex=expo(10,nc);
    }    
            
    return((sinal*val/pot)*ex);
}

main()
{
    double soma;
    char c,linha[1000];
    int i=0;
    
    soma=0;
    printf("Digite a string a ser convertida\n\n");
    c=getchar();
    while(c!='\n')
    {
        linha[i]=c;
        c=getchar();
        i++;
    }
    linha[i]='{TEXTO}';
    printf("\n%f\n",soma+=atof(linha));
}