class Solution {
public:
string complexNumberMultiply(string num1, string num2) {
string res="";
int index=0;
int real1=0;
int real2=0;
int imag1=0;
int imag2=0;
int temp=0;
int symbol=1;
if(num1[index]=='-')
{
symbol=-1;
index++;
}
while(num1[index]!='+'){
temp=temp*10+num1[index]-'0';
index++;
}
real1=temp*symbol;
temp=0;
symbol=1;
index++;
if(num1[index]=='-')
{
symbol=-1;
index++;
}
while(num1[index]!='i'){
temp=temp*10+num1[index]-'0';
index++;
}
imag1=temp*symbol;
//第二个复数计算
index=0;
temp=0;
symbol=1;
if(num2[index]=='-')
{
symbol=-1;
index++;
}
while(num2[index]!='+'){
temp=temp*10+num2[index]-'0';
index++;
}
real2=temp*symbol;
symbol=1;
temp=0;
index++;
if(num2[index]=='-')
{
symbol=-1;
index++;
}
while(num2[index]!='i'){
temp=temp*10+num2[index]-'0';
index++;
}
imag2=temp*symbol;
int resReal=real1*real2-imag1*imag2;
int resImag=real1*imag2+real2*imag1;
res=to_string(resReal)+"+"+to_string(resImag)+"i";
return res;
}
};